EBM 5

A/an __________ is the probability that the test statistic represents normal variation. It is compared to the level of alpha selected for the study. If the number is less than alpha (or alpha-halves in most cases), then the result is deemed statistically significant.

P-value

__________ is when researchers compare treatment groups that include only those patients who completed the treatment originally allocated.

Per-protocol analysis

A __________ is an inactive substance or treatment that looks the same as, and is given in the same way as, an active drug or intervention/treatment being studied.

Placebo

__________ is a change in a person's symptoms as a result of getting an inactive substance or treatment that looks the same as, and is given in the same way as, an active drug or intervention/treatment being studied.

Placebo effect

*Use the following abstract to answer the question below.AbstractBACKGROUND: We previously reported that a randomized controlled trial of antenatal micronutrient supplements in rural Nepal decreased the risk of low birth weight by ~15%.OBJECTIVE: The objective was to examine the effects of micronutrient supplementation on growth and body composition in children of supplemented mothers through school age.DESIGN: Mothers received 1 of 5 micronutrient supplements daily: folic acid, folic acid + iron, folic acid + iron + zinc, multiple micronutrients, or a control. All of the supplements contained vitamin A. Children born during this trial were revisited at age 6-8 y to measure height, weight, mid-upper arm circumference, waist circumference, and triceps and subscapular skinfold thicknesses. Arm fat and muscle area were estimated by using standard formulas, and height-for-age, weight-for-age, and body mass index-for-age z scores were calculated by using the World Health Organization growth standard.RESULTS: Of the 3771 surviving children, 3324 were revisited and consented to anthropometric measurements. Maternal supplementation with folic acid + iron + zinc resulted in an increase in mean height (0.64 cm; 95% CI: 0.04, 1.25) and a reduction in mean triceps skinfold thickness (20.25 mm; 95% CI: 20.44, 20.06), subscapular skinfold thickness (20.20 mm; 95% CI: 20.33, 20.06), and arm fat area (20.18 cm2; 20.34, 20.01). No significant differences were found between groups in mean weight or body mass index-for-age z scores, waist circumference, or arm muscle area. Other micronutrient combinations including a multiple micronutrient formulation failed to show a growth benefit.CONCLUSION: Antenatal supplementation with zinc may benefit child growth, particularly in areas where a deficiency of this nutrient is common. What is the data type for the difference in height between the different micronutrient groups and the control group at 6-8 years?

Quantitative

The sample size, in the qualitative paradigm, is determined by the number of participants needed to achieve __________ of all categories and codes.

Saturation

_________ is a set of attributes of each type of data, including the distance between points, the presence of an absolute zero, and whether the points on the scale are ordered.

Scale

_________ is the theory, procedures, and methodology by which data are summarized.

Statistics

__________ test the null hypothesis that the two treatments are equivalent.

Superiority trials

__________ determine if variables change in association to other variables (e.g., arthritis incidence increases with age or heart disease increases with incidence of diabetes).

Tests for relationships

In __________, researchers attempt to generalize a phenomenon measured in a sample to the population represented by the sample.

inferential statistics

A/an __________ is a study in which the research question asks whether the experimental intervention is not substantially worse than the control intervention.

non-inferiority trial

The total number of subjects included in a study is referred to as:

sample size

A __________ is a list or other record of all the elements in the population from which the sampling units are drawn. It defines a study's accessible population and represents the source of the subjects for the study

sampling frame

A __________ is a procedure or device that appears to be the same as the actual procedure or device being studied but does not contain active processes or components.

sham intervention

_________ is a form of probability sampling that allows every member of the population to have an equal chance of being selected for the study.

simple random sample

__________ is the progress of study participants, beginning with recruitment and ending with the last data element collected from them.

study flow

*In an RCT on weight loss, comparing low-carbohydrate diet (<40 g/d) with low-fat diet (<30% of daily energy intake from fat [<7% saturated fat]), the researchers determined that low-carbohydrate diet resulted in greater weight loss: mean difference in change, -3.5 kg (95% CI, -5.6 to -1.4 kg) Based on the confidence interval provided, what is the lowest amount of mean difference in weight change expected among the population if the population followed the low-carbohydrate diet?

*-1.4 kg

*Identify the primary outcome measure in the following abstract. For the primary outcome measure, select the value that represents the point estimate.AbstractBACKGROUND: Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations.OBJECTIVE: To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors.DESIGN: A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271)SETTING: A large academic medical center.PARTICIPANTS: 148 men and women without clinical cardiovascular disease and diabetes.INTERVENTION: A low-carbohydrate (<40 g/d) or low-fat (<30% of daily energy intake from total fat [<7% saturated fat]) diet. Both groups received dietary counseling at regular intervals throughout the trial.MEASUREMENTS: Data on weight (kg), cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months, with mean difference in change in weight being the primary outcome of interest.RESULTS: Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, -3.5 kg [95% CI, -5.6 to -1.4 kg]; P = 0.002), fat mass (mean difference in change, -1.5% [CI, -2.6% to -0.4%]; P = 0.011), ratio of total-high-density lipoprotein (HDL) cholesterol (mean difference in change, -0.44 [CI, -0.71 to -0.16]; P = 0.002), and triglyceride level (mean difference in change, -0.16 mmol/L [-14.1 mg/dL] [CI, -0.31 to -0.01 mmol/L {-27.4 to -0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P < 0.001) than those on the low-fat diet.LIMITATION: Lack of clinical cardiovascular disease end points.CONCLUSION: The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.

*-3.5kg

*Use the following abstract to answer the question below.AbstractBACKGROUND: We previously reported that a randomized controlled trial of antenatal micronutrient supplements in rural Nepal decreased the risk of low birth weight by ~15%.OBJECTIVE: The objective was to examine the effects of micronutrient supplementation on growth and body composition in children of supplemented mothers through school age.DESIGN: Mothers received 1 of 5 micronutrient supplements daily: folic acid, folic acid + iron, folic acid + iron + zinc, multiple micronutrients, or a control. All of the supplements contained vitamin A) Children born during this trial were revisited at age 6-8 y to measure height, weight, mid-upper arm circumference, waist circumference, and triceps and subscapular skinfold thicknesses. Arm fat and muscle area were estimated by using standard formulas, and height-for-age, weight-for-age, and body mass index-for-age z scores were calculated by using the World Health Organization growth standard.RESULTS: Of the 3771 surviving children, 3324 were revisited and consented to anthropometric measurements. Maternal supplementation with folic acid + iron + zinc resulted in an increase in mean height (0.64 cm; 95% CI: 0.04, 1.25) and a reduction in mean triceps skinfold thickness (-0.25 mm; 95% CI: -0.44, -0.06), subscapular skinfold thickness (-0.20 mm; 95% CI: -0.33, -0.06), and arm fat area (-0.18 cm2; 20.34, -0.01). No significant differences were found between groups in mean weight or body mass index-for-age z scores, waist circumference, or arm muscle area. Other micronutrient combinations including a multiple micronutrient formulation failed to show a growth benefit.CONCLUSION: Antenatal supplementation with zinc may benefit child growth, particularly in areas where a deficiency of this nutrient is common. Based on the confidence interval provided, what is the lowest amount of difference in height at 6-8 years expected between the folic acid + iron + zinc and the control group?

*0.04

*Use the following abstract to answer the question below. Abstract BACKGROUND: We previously reported that a randomized controlled trial of antenatal micronutrient supplements in rural Nepal decreased the risk of low birth weight by ~15%. OBJECTIVE: The objective was to examine the effects of micronutrient supplementation on growth and body composition in children of supplemented mothers through school age. DESIGN: Mothers received 1 of 5 micronutrient supplements daily: folic acid, folic acid + iron, folic acid + iron + zinc, multiple micronutrients, or a control. All of the supplements contained vitamin A. Children born during this trial were revisited at age 6-8 y to measure height, weight, mid-upper arm circumference, waist circumference, and triceps and subscapular skinfold thicknesses. Arm fat and muscle area were estimated by using standard formulas, and height-for-age, weight-for-age, and body mass index-for-age z scores were calculated by using the World Health Organization growth standard. RESULTS: Of the 3771 surviving children, 3324 were revisited and consented to anthropometric measurements. Maternal supplementation with folic acid + iron + zinc resulted in an increase in mean height (0.64 cm; 95% CI: 0.04, 1.25) and a reduction in mean triceps skinfold thickness (-0.25 mm; 95% CI: -0.44, -0.06), subscapular skinfold thickness (-0.20 mm; 95% CI: -0.33, -0.06), and arm fat area (-0.18 cm2; 20.34, -0.01). No significant differences were found between groups in mean weight or body mass index-for-age z scores, waist circumference, or arm muscle area. Other micronutrient combinations including a multiple micronutrient formulation failed to show a growth benefit. CONCLUSION: Antenatal supplementation with zinc may benefit child growth, particularly in areas where a deficiency of this nutrient is common. Identify the point estimate for the difference in height between the folic acid + iron + zinc and the control group at 6-8 years?

*0.64

*In a study on the effects of cognitive behavioral therapy (CBT) as a treatment for insomnia, the researchers utilized the Pittsburgh Sleep Quality Index (PSQI) as their primary outcome measure. The study included a sample of 480 adults, 278 female (57.9%). With the PSQI, a reduction in score indicates improvement in sleep quality. Prior research has shown that a 5% change on the PSQI is a clinically important outcome that matters. In the group that received no intervention (the control group), there was a 2% reduction in PSQI score. In the CBT group, there was a 10.5% reduction in PSQI score.The authors reported: ""the intervention (CBT) was associated with a significant improvement in sleep quality. With alpha < 0.05 the percent difference between groups (7.5%) was statistically significant (p-value=0.001; 95% CI: 7.0%-8.0%).""From this study, which of the following is a descriptive statistic?

*2% reduction in PSQI in the control group

*What is used to display the frequencies or proportions of observations in a categorical scale data set?

*Bar graph

*Read the following description of the Framingham Heart Study (which is a famous, longitudinal study): Cardiovascular disease (CVD) is the leading cause of death and serious illness in the United States. In 1948, the Framingham Heart Study - under the direction of the National Heart Institute (now known as the National Heart, Lung, and Blood Institute or NHLBI) - embarked on an ambitious project in health research. At the time, little was known about the general causes of heart disease and stroke, but the death rates for CVD had been increasing steadily since the beginning of the century and had become an American epidemic. The Framingham Heart Study became a joint project of the National Heart, Lung and Blood Institute and Boston University. The objective of the Framingham Heart Study is to identify the common factors or characteristics that contribute to CVD by following its development over a long period of time in a large group of participants who had not yet developed overt symptoms of CVD or suffered a heart attack or stroke. The researchers recruited 5,209 men and women between the ages of 30 and 62 from the town of Framingham, Massachusetts, and began the first round of extensive physical examinations and lifestyle interviews that they would later analyze for common patterns related to CVD development. Since 1948, the subjects have continued to return to the study every two years for a detailed medical history, physical examination, and laboratory tests, and in 1971, the Study enrolled a second generation - 5,124 of the original participants' adult children and their spouses - to participate in similar examinations. -quoted from: http://www.framinghamheartstudy.org/ This study is an example of what type of research?

*Cohort study

*In the following abstract, identify the primary outcome measure reported. What is the data scale for the primary outcome measure? Abstract BACKGROUND: Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations. OBJECTIVE: To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors. DESIGN: A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271) SETTING: A large academic medical center. PARTICIPANTS: 148 men and women without clinical cardiovascular disease and diabetes. INTERVENTION: A low-carbohydrate (<40 g/d) or low-fat (<30% of daily energy intake from total fat [<7% saturated fat]) diet. Both groups received dietary counseling at regular intervals throughout the trial. MEASUREMENTS: Data on weight (kg), cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months, with mean difference in change in weight being the primary outcome of interest. RESULTS: Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, -3.5 kg [95% CI, -5.6 to -1.4 kg]; P = 0.002), fat mass (mean difference in change, -1.5% [CI, -2.6% to -0.4%]; P = 0.011), ratio of total-high-density lipoprotein (HDL) cholesterol (mean difference in change, -0.44 [CI, -0.71 to -0.16]; P = 0.002), and triglyceride level (mean difference in change, -0.16 mmol/L [-14.1 mg/dL] [CI, -0.31 to -0.01 mmol/L {-27.4 to -0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P < 0.001) than those on the low-fat diet. LIMITATION: Lack of clinical cardiovascular disease end points. CONCLUSION: The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.

*Continuous

*What is used to display the frequencies or proportions of observations in a continuous scale data set?

*Histogram

*In a normally-shaped distribution, where is the median located?

*In the same place as the mean

*14: In a normally-shaped distribution, where is the mean located?

*In the same place as the median

*What item tells us the most frequently occurring value in a distribution?

*Mode

*Read the following description of the Koppos et al study that compared two medications for treating multiple sclerosis: The most common medication for treatment of multiple sclerosis interferon beta-1a. A new medication, daclizumab HYP, has been developed showing a similar efficacy to interferon beta-1a. Both medications have been found to be safe in small studies involving samples sizes ranging from 50 to 70 subjects.1,2,3 Further controlled clinical trials established efficacy of daclizumab HYP, identifying short term side effects and risks of the medications.4,5 It is not known, however, if daclizumab HYP is superior to interferon beta-1a in terms of the frequency and severity of relapse episodes, nor the degree of remission that occurs at the end of relapse periods. PURPOSE: A randomized, double-blind, active-controlled, multi-site, national clinical trial was performed (n = 1,841) to compare daclizumab HYP (administered subcutaneously at a dose of 150 mg every 4 weeks) with interferon beta-1a (administered intramuscularly at a dose of 30 µg once weekly) for up to 144 weeks. The primary end point was the annualized relapse rate. RESULTS: The annualized relapse rate was lower with daclizumab HYP than with interferon beta-1a (0.22 vs. 0.39; 45% lower rate with daclizumab HYP; P<0.001). At week 144, the estimated incidence of disability progression confirmed at 12 weeks was 16% with daclizumab HYP and 20% with interferon beta-1a (P=0.16). Serious adverse events, excluding relapse of multiple sclerosis, were reported in 15% of the patients in the daclizumab HYP group and in 10% of those in the interferon beta-1a group. Infections were more common in the daclizumab HYP group than in the interferon beta-1a group (in 65% vs. 57% of the patients, including serious infection in 4% vs. 2%), as were cutaneous events such as rash or eczema (in 37% vs. 19%, including serious events in 2% vs. <1%) and elevations in liver aminotransferase levels that were more than 5 times the upper limit of the normal range (in 6% vs. 3%). CONCLUSIONS: Among patients with relapsing-remitting multiple sclerosis, daclizumab HYP showed efficacy superior to that of interferon beta-1a with regard to the annualized relapse rate and lesions, as assessed by means of MRI, but was not associated with a significantly lower risk of disability progression confirmed at 12 weeks. The rates of infection, rash, and abnormalities on liver-function testing were higher with daclizumab HYP than with interferon beta-1a. This study is an example of what type of research?

*Phase III clinical trial

*6: In the following abstract, identify the primary outcome measure reported. What is the data type for the primary outcome measure?AbstractBACKGROUND: Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations.OBJECTIVE: To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors.DESIGN: A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271)SETTING: A large academic medical center.PARTICIPANTS: 148 men and women without clinical cardiovascular disease and diabetes.INTERVENTION: A low-carbohydrate (<40 g/d) or low-fat (<30% of daily energy intake from total fat [<7% saturated fat]) diet. Both groups received dietary counseling at regular intervals throughout the trial.MEASUREMENTS: Data on weight (kg), cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months, with mean difference in change in weight being the primary outcome of interest.RESULTS: Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, -3.5 kg [95% CI, -5.6 to -1.4 kg]; P = 0.002), fat mass (mean difference in change, -1.5% [CI, -2.6% to -0.4%]; P = 0.011), ratio of total-high-density lipoprotein (HDL) cholesterol (mean difference in change, -0.44 [CI, -0.71 to -0.16]; P = 0.002), and triglyceride level (mean difference in change, -0.16 mmol/L [-14.1 mg/dL] [CI, -0.31 to -0.01 mmol/L {-27.4 to -0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P < 0.001) than those on the low-fat diet.LIMITATION: Lack of clinical cardiovascular disease end points.CONCLUSION: The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.

*Quantitative

*Use the following abstract to answer the question below. Abstract BACKGROUND: We previously reported that a randomized controlled trial of antenatal micronutrient supplements in rural Nepal decreased the risk of low birth weight by ~15%. OBJECTIVE: The objective was to examine the effects of micronutrient supplementation on growth and body composition in children of supplemented mothers through school age. DESIGN: Mothers received 1 of 5 micronutrient supplements daily: folic acid, folic acid + iron, folic acid + iron + zinc, multiple micronutrients, or a control. All of the supplements contained vitamin A. Children born during this trial were revisited at age 6-8 y to measure height, weight, mid-upper arm circumference, waist circumference, and triceps and subscapular skinfold thicknesses. Arm fat and muscle area were estimated by using standard formulas, and height-for-age, weight-for-age, and body mass index-for-age z scores were calculated by using the World Health Organization growth standard. RESULTS: Of the 3771 surviving children, 3324 were revisited and consented to anthropometric measurements. Maternal supplementation with folic acid + iron + zinc resulted in an increase in mean height (0.64 cm; 95% CI: 0.04, 1.25) and a reduction in mean triceps skinfold thickness (-0.25 mm; 95% CI: -0.44, -0.06), subscapular skinfold thickness (-0.20 mm; 95% CI: -0.33, -0.06), and arm fat area (-0.18 cm2; 20.34, -0.01). No significant differences were found between groups in mean weight or body mass index-for-age z scores, waist circumference, or arm muscle area. Other micronutrient combinations including a multiple micronutrient formulation failed to show a growth benefit. CONCLUSION: Antenatal supplementation with zinc may benefit child growth, particularly in areas where a deficiency of this nutrient is common. What is the data scale for the difference in height between the different micronutrient groups and the control group at 6-8 years?

*Ratio

*Based on the study abstract below, select the descriptive statistic from the following answers. AbstractOBJECTIVES: To examine change in urinary incontinence before and after bariatric surgery and to identify factors associated with improvement and remission among women and men in the first 3 years after bariatric surgery.MAIN OUTCOMES AND MEASURES: The frequency and type of urinary incontinence episodes in the past 3 months were assessed using a validated questionnaire. Prevalent urinary incontinence was defined as at least weekly urinary incontinence episodes, and remission was defined as change from prevalent urinary incontinence at baseline to less than weekly urinary incontinence episodes at follow-up.RESULTS: Of 2458 participants, 1987 (80.8%) completed baseline and follow-up assessments. At baseline, the median age was 47 years (age range, 18-78 years), the median body mass index was 46 kg/m2 (range, 34-94 kg/m2), and 1565 of 1987 (78.8%) were women. Urinary incontinence was more prevalent among women (49.3%; 95% CI, 46.9%-51.9%) than men (21.8%; 95% CI, 18.2%-26.1%) (P?CONCLUSIONS AND RELEVANCE: Among women and men with severe obesity, bariatric surgery was associated with substantially reduced urinary incontinence over 3 years. Improvement in urinary incontinence may be an important benefit of bariatric surgery.From this study, which of the following is a descriptive statistic?

*The 3-year urinary incontinence prevalence was 24.8%.

*Read the following abstract, paying close attention to the methods; determine which of the following statements is true with regard to the outcome measures.AbstractBACKGROUND: Barium enema (BE) is widely available for diagnosis of colorectal cancer despite concerns about its accuracy and acceptability. Computed tomographic colonography (CTC) might be a more sensitive and acceptable alternative. We aimed to compare CTC and BE for diagnosis of colorectal cancer or large polyps in symptomatic patients in clinical practice.METHODS: This pragmatic multicentre randomised trial recruited patients with symptoms suggestive of colorectal cancer from 21 UK hospitals. Eligible patients were aged 55 years or older and regarded by their referring clinician as suitable for radiological investigation of the colon. Patients were randomly assigned (2:1) to BE or CTC by computer-generated random numbers, in blocks of six, stratified by trial centre and sex. We analysed the primary outcome - diagnosis of colorectal cancer, or large (=10 mm) polyps - by intention to treat. The trial is an International Standard Randomised Controlled Trial, number 95152621.FINDINGS: 3838 patients were randomly assigned to receive either BE (n=2553) or CTC (n=1285). Thirty-four patients withdrew consent, leaving for analysis 2527 assigned to BE and 1277 assigned to CTC). The detection rate of colorectal cancer or large polyps was significantly higher in patients assigned to CTC than in those assigned to BE (93 [7.3%] of 1277 vs 141 [5.6%] of 2527, relative risk 1.31, 95% CI 1.01-1.68; p=0.0390). CTC missed 3 of 45 colorectal cancers, and BE missed 12 of 85. The rate of additional colonic investigation was higher after CTC than after BE (283 [23.5%] of 1206 CTC patients had additional investigation vs 422 [18.3%] of 2300 BE patients; p=0.0003), due mainly to a higher polyp detection rate. Serious adverse events were rare.INTERPRETATION: CTC is a more sensitive test than BE. Our results suggest that CTC should be the preferred radiological test for patients with symptoms suggestive of colorectal cancer.FUNDING: NIHR Health Technology Assessment Programme, NIHR Biomedical Research Centres funding scheme, Cancer Research UK, EPSRC Multidisciplinary Assessment of Technology Centre for Healthcare, and NIHR Collaborations for Leadership in Applied Health Research and Care.

*The primary outcome measure was the presence of large polyps (=10 mm) or colorectal cancer diagnosis.

*Read the following abstract, paying close attention to the methods, and determine which of the following statements is true with regard to the outcome measures.AbstractBACKGROUND: Low back pain (LBP) is common in primary care. Guidelines recommend delaying referrals for physical therapy.OBJECTIVE: To evaluate whether early physical therapy (manipulation and exercise) is more effective than usual care in improving disability for patients with LBP fitting a decision rule.DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial with 220 participants recruited between March 2011 and November 2013. Participants with no LBP treatment in the past 6 months, aged 18 through 60 years (mean age, 37.4 years [SD,?10.3]), an Oswestry Disability Index (ODI) score of 20 or higher, symptom duration less than 16 days, and no symptoms distal to the knee in the past 72 hours were enrolled following a primary care visit.INTERVENTIONS: All participants received education. Early physical therapy (n?=?108) consisted of 4 physical therapy sessions. Usual care (n?=?112) involved no additional interventions during the first 4 weeks.MAIN OUTCOMES AND MEASURES: Primary outcome was change in the ODI score (range: 0-100; higher scores indicate greater disability; minimum clinically important difference, 6 points) at 3 months. Secondary outcomes included changes in the ODI score at 4-week and 1-year follow-up, and change in pain intensity, Pain Catastrophizing Scale (PCS) score, fear-avoidance beliefs, quality of life, patient-reported success, and health care utilization at 4-week, 3-month, and 1-year follow-up.RESULTS: One-year follow-up was completed by 207 participants (94.1%). Using analysis of covariance, early physical therapy showed improvement relative to usual care in disability after 3 months (mean ODI score: early physical therapy group, 41.3 [95% CI, 38.7 to 44.0] at baseline to 6.6 [95% CI, 4.7 to 8.5] at 3 months; usual care group, 40.9 [95% CI, 38.6 to 43.1] at baseline to 9.8 [95% CI, 7.9 to 11.7] at 3 months; between-group difference, -3.2 [95% CI, -5.9 to -0.47], P?=?.02). A significant difference was found between groups for the ODI score after 4 weeks (between-group difference, -3.5 [95% CI, -6.8 to -0.08], P?=?.045]), but not at 1-year follow-up (between-group difference, -2.0 [95% CI, -5.0 to 1.0], P?=?.19). There was no improvement in pain intensity at 4-week, 3-month, or 1-year follow-up (between-group difference, -0.42 [95% CI, -0.90 to 0.02] at 4-week follow-up; -0.38 [95% CI, -0.84 to 0.09] at 3-month follow-up; and -0.17 [95% CI, -0.62 to 0.27] at 1-year follow-up). The PCS scores improved at 4 weeks and 3 months but not at 1-year follow-up (between-group difference, -2.7 [95% CI, -4.6 to -0.85] at 4-week follow-up; -2.2 [95% CI, -3.9 to -0.49] at 3-month follow-up; and -0.92 [95% CI, -2.7 to 0.61] at 1-year follow-up). There were no differences in health care utilization at any point.CONCLUSIONS AND RELEVANCE: Among adults with recent-onset LBP, early physical therapy resulted in statistically significant improvement in disability, but the improvement was modest and did not achieve the minimum clinically important difference compared with usual care.

*There were no primary outcome measures reported in the abstract.

*In a data set with an even number of observations, the median is the:

*average of the two observations at the center of the ordered observations.

*In a study on an insomnia medication, the researchers used a device that was later found not to be an accurate method for detecting sleep. This is an example of:

*measurement error.

*A _____ is a single number, such as a sample mean or incidence rate, that is associated with an outcome measure reported in a study. It is one of the set of reported values for the outcome measure. It tells us what the value for the outcome was among the sample and cannot tell us precisely what the value will be in the population because it is only a single value, rather than a range of values.

*point estimate

*In a study on an insomnia medication, the researchers selected subjects who did not have insomnia. This is an example of:

*sampling bias

_________ compares a statistic (i.e., a mean or a proportion) between two or more groups (such as a t-test or ANOVA).

A test for differences

Which statement about the following data types is true? 1 - Continuous 2 - Interval 3 - Ratio

All three are quantitative data.

___________ is the probability of a Type I error. It is selected by the investigators during the design of the research. It represents the researchers' risk of incorrectly rejecting the null hypothesis (of saying there is a difference when in fact there is not).

Alpha

A __________ displays the progress of research participants through the study, beginning with recruitment and ending with the last data element collected from them in a positivistic study.

CONSORT diagram

__________ data have the following characteristics: data are ordered; the distance between each unit is equal; a definable zero point; and values can be added, subtracted, multiplied, or divided and can take on any value within their intervals.

Continuous

___________ is when researchers base the sampling frame on individuals to whom they have easy access.

Convenience sampling

_________ make predictions about a population based on data drawn from a sample.

Inferential statistics

__________ is the generic term to refer to all of the tools utilized to collect data.

Instrumentation

__________ is when researchers compare the treatment groups that include all patients as originally allocated after randomization.

Intention-to-treat analysis

In a study, the p-value associated with the test statistic was 0.43 (alpha < 0.05). What is the meaning of this p-value?

It means there is a 43% chance the test statistic represents normal variability and the result is, therefore, not statistically significant.

In a study, the p-value associated with the test statistic was 0.001 (alpha < 0.05). What is the meaning of this p-value?

It means there is less than a 0.1 percent chance that the test statistic represents normal variability.

In a study, the p-value associated with the test statistic was 0.0043 (alpha < 0.05). What is the meaning of this p-value?

It means there is less than a 0.43 percent chance that the test statistic represents normal variability

___________ is a procedure for selecting research subjects that occurs in several steps. This procedure often is used when dealing with very large sampling frames and when researchers want to ensure that every subgroup is included. For example, using this procedure research might employ the following steps: 1. Divide the United States into geographic clusters and randomly select states from each region. 2. Stratify cities and towns in the selected states into population density and rurality groups, then randomly select cities and towns from each group. 3. Stratify selected cities and towns into ethnic groups by voting districts and randomly select districts from each ethnic group.

Multistage sample

A Likert scale is an example of which type of data?

Ordinal