The usefulness of meta-analyses in treatment decisions.
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Biomedical subjects
Publications and source records attributed to I Shrier.
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OBJECTIVE: Although many clinicians believe high growth leads to inflexibility, which may lead to lower extremity pain, the only prospective data suggest growth is unrelated to flexibility. However, it is still possible that growth and/or flexibility are related to pain even if they are not related to each other. We investigated the incidence of leg pain in adolescents to determine whether high growth spurt and/or poor flexibility are risk factors for the development of lower extremity pain. METHODS: Repeated measures, prospective cohort study of urban high school students aged 12-18. Subjects were measured at baseline and at 6 and 12 months for flexibility of hamstrings and quadriceps and with the sit-and-reach test. Participants completed a detailed questionnaire on recreational activity, occupational activities, psychosocial variables, and musculoskeletal pain. RESULTS: Poor hamstring flexibility (odds ratio 0.99, confidence interval 0.97-1.01), poor quadriceps flexibility (OR 1.01, CI 0.99-1.03), poor sit-and-reach flexibility (OR 0.99, CI 0.99-1.01), and growth (OR 0.93, CI 0.50-1.71) were not related to the development of lower extremity pain. There was an association between lower extremity pain and occupational activities (OR 2.08, CI 1.45-2.98) and poor mental health (per 1 SD change, OR 1.41, CI 1.19-1.67). CONCLUSION: Neither growth nor flexibility is related to the development of lower extremity pain in adolescents. A poor mental health score and occupational activities may be associated with the development of lower extremity pain.
BACKGROUND: Small bowel obstruction (SBO) is a major cause of morbidity and financial expenditure in hospitals around the world. The leading cause of SBO in the western world has become adhesions. The goal of this study was to determine the causes of SBO. METHODS: The medical records of all patients admitted to one hospital between 1986 and 1996 with the diagnosis of SBO were reviewed retrospectively. This included 552 patients accounting for 1,001 admissions. RESULTS: The etiology of SBO was adhesions (74%), Crohn's disease (7%), neoplasia (5%), hernia (2%), radiation (1%), and miscellaneous (11%). Patients with Crohn's disease were younger than patients with other etiologies. Surprisingly, recurrence rates were similar for patients treated operatively as for those treated nonoperatively with the exception in the hernia group where higher recurrence rates were noted for patients initially treated in a nonoperative manner. CONCLUSION: The most common cause of SBO is adhesions followed by Crohn's disease and neoplasia.
Pharmacologic doses of folic acid are commonly used to reduce the hyperhomocysteinemia of end-stage renal disease (ESRD). Vitamin B12 acts at the same metabolic locus as folic acid, but information is lacking about the specific effects of high doses of this vitamin on homocysteine levels in renal failure. We therefore compared the plasma homocysteine concentrations of maintenance hemodialysis patients in two McGill University-affiliated urban tertiary-care medical centers that differed in the use of vitamin B12 and folic acid therapy. Patients in the first hemodialysis unit are routinely prescribed high-dose folic acid (HI-F, 6 mg/d), whereas those in the second unit receive high-dose vitamin B12 in the form of a monthly 1-mg intravenous injection, along with conventional oral folic acid (HI-B12, 1 mg/d). Predialysis homocysteine was 23.4 +/- 6.8 micromol/L (mean +/- SD) in the HI-F unit and 18.2 +/- 6.1 micromol/L in the HI-B12 unit (P < .002). Postdialysis homocysteine was 14.5 +/- 4.1 in the HI-F unit and 10.6 +/- 3.4 micromol/L in the HI-B12 unit (P = .0001). Multiple regression analysis indicated that high-dose parenteral vitamin B12 was associated with a lower homocysteine concentration even after controlling for the potential confounders of sex, serum urea, serum creatinine, urea reduction ratio, and plasma cysteine. Because this was a cross-sectional observational study, we cannot exclude the possibility that unidentified factors, rather than the different vitamin therapies, account for the different homocysteine levels in the two units. Careful prospective studies of the homocysteine-lowering effect of high-dose parenteral vitamin B12 in ESRD should be undertaken.
BACKGROUND: Small bowel obstruction (SBO) is a major cause of morbidity and financial expenditure. The goals of this study were to determine factors predisposing to adhesive SBO, to note the long-term prognosis and recurrence rates for operative and non-operative treatment, to elicit the complication rate of operations and to highlight factors predictive of recurrence. METHODS: The medical records of all patients admitted to one hospital between 1986 and 1996 with the diagnosis of SBO were reviewed retrospectively. This included 410 patients accounting for 675 admissions. RESULTS: The frequency of previous operation by procedure type was colorectal surgery (24 per cent), followed by gynaecological surgery (22 per cent), herniorrhaphy (15 per cent) and appendicectomy (14 per cent). A history of colorectal surgery (odds 2.7) and vertical incisions (odds 2.5) tended to predispose to multiple matted adhesions rather than an obstructive band. At initial admission 36 per cent of patients were treated by means of operation. As the number of admissions increased, the recurrence rate increased while the time interval between admissions decreased. Patients with an adhesive band had a 25 per cent readmission rate, compared with a 49 per cent rate for patients with matted adhesions (P<0.004). At the initial admission 36 per cent of patients were treated surgically. Patients treated without operation had a 34 per cent readmission rate, compared with 32 per cent for those treated surgically (P not significant), a shorter time to readmission (median 0.7 versus 2.0 years; P<0.05), no difference in reoperation rate (14 versus 11 per cent; P not significant) and fewer inpatient days over all admissions (4 versus 12 days; P<0.0001). CONCLUSION: The likelihood of reobstruction increases and the time to reobstruction decreases with increasing number of previous episodes of obstruction. Patients with matted adhesions have a greater recurrence rate than those with band adhesions. Non-operative treatment for adhesions in stable patients results in a shorter hospital stay and similar recurrence and reoperation rates, but a reduced interval to reobstruction when compared with operative treatment.
Acute Atraumatic Compartment Syndrome (AACS) can be a potentially life and limb threatening complication of either drug abuse or medication injection. Prompt recognition followed by emergency fasciotomy is required to avoid permanent disability. A better understanding of the different clinical presentations may lead to improved outcomes through more expedient diagnosis and treatment. We describe five new cases of AACS caused by illicit drug abuse within the McGill University Hospitals, with a review of all 102 similar patients previously documented in the literature between January 1970 and May 1997. The average age for all cases was 29 years, with 74% being male. The presence of edema, pain, tension, and skin changes were the most frequent symptoms and signs reported. There appear to be two distinct mechanisms of poisoning-induced AACS: (1) direct vasotoxicity and (2) limb compression caused by prolonged comatose state. Direct vasotoxicity is more likely to lead to eventual amputation, whereas prolonged limb compression is more likely to progress to systemic complications such as azotemia, hypotension, cardiac arrhythmia, and renal failure (Crush Syndrome). Long-term sequelae of motor loss, sensory disruption, and development of contracture were common in AACS of both causes. Because Compartment Syndrome is a surgical emergency, primary care and emergency physicians must have a high index of suspicion to promptly recognize and treat this problem.
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OBJECTIVE: To determine the efficacy and long-term prognosis for operative versus nonoperative treatment of small-bowel obstruction (SBO) secondary to malignant disease. DESIGN: A chart review. SETTING: A university-affiliated teaching hospital. PATIENTS: The medical records of all patients with malignant disease as the established etiology of their obstruction who presented to the Sir Mortimer B. Davis-Jewish General Hospital, Montreal, between 1986 and 1996 were reviewed. There were 32 patients accounting for 74 admissions. INTERVENTIONS: Selective nonoperative management and exploratory laparotomy, immediate or delayed. MAIN OUTCOME MEASURES: The value of nonoperative management and need for operation. RESULTS: Colorectal and ovarian neoplasms were the principal primary malignant diseases that led to SBO. The median time between diagnosis of the malignant disease and SBO was 1.1 years. At their initial presentation, 80% of patients were treated by operation, but 47% of these patients had an initial trial of nonoperative treatment. Reobstruction occurred in 57% of patients who were operated on compared with 72% of patients who were not. The median time to reobstruction was 17 months for patients who underwent operation compared with 2.5 months for patients who did not. Also, 71% of patients were alive and symptom free 30 days after discharge from operative treatment compared with 52% after nonoperative treatment. Postoperative morbidity was 67%. Mortality was 13%, and 94% of patients eventually died from complications of their primary disease. CONCLUSIONS: SBO secondary to malignant disease usually indicates a grim prognosis. Operative treatment has better outcome than nonoperative management in terms of symptom free interval and reobstruction rates. However, it is marked by high postoperative morbidity. We recommend that, after short trial of nasogastric decompression, patients with obstruction secondary to malignant disease be operated on if clinical factors indicate they they will survive the operation.
STUDY DESIGN: A prospective, repeated-measures cohort design with high school students from Montreal, Canada. OBJECTIVES: To determine whether smoking was a risk factor for the development of low back pain or other musculoskeletal pain in a cohort of adolescents. SUMMARY OF BACKGROUND DATA: Smoking has been associated with low back pain in adults. Many adolescents smoke, and the prevalence of low back pain in this age group is 30%. A history of low back pain is predictive of future problems. METHODS: A total of 502 students from grades 7 to 9 were assessed from 3 schools. Data were collected at 3 times: at the beginning of the study, at 6 months, and at the end of a 12-month period. Students responded to a questionnaire addressing musculoskeletal health and life-style factors, which included smoking. Measurements of height, weight, trunk and leg flexibility, and trunk strength were obtained. Low back pain occurring at a frequency of at least once a week in the past 6 months was defined as the outcome. Multivariate methods were used to model the repeated-measures dichotomous outcome as a function of smoking and other covariates. RESULTS: Smokers experienced low back pain more than nonsmokers (odds ratio, 2.4; 95% confidence interval, 1.3-6.0). There was also a dose-response relationship between amount smoked and development of low back pain. Smokers tended to experience more upper limb or lower limb pain than nonsmokers, although this result was not significant. CONCLUSIONS: Smoking was found to increase the risk for low back pain in this cohort of adolescents.
The incidence of hepatocellular carcinoma in North America is increasing. Current debate focuses on whether interferon administered to cirrhotic patients-with or without biochemical or virologic response-delays or prevents cancer of the liver. Review of the literature revealed several studies that showed improvement in or delay in progression of histologic fibrosis in patients with hepatitis C virus (HCV) infection. In patients with hepatitis B virus (HBV) infection, conversion to the nonreplicative stage may be associated with histologic improvement. However, only 11 studies (6 of HCV, 3 of HBV, and 2 of HCV and HBV) compared development of hepatocellular carcinoma in interferon-treated patients with cirrhosis and cirrhotic patients who were not treated with interferon. Although no firm statistical conclusions could be drawn, the literature suggests that interferon therapy may prevent hepatocellular carcinoma in patients with cirrhosis, particularly those infected with HCV. Interferon treatment cannot be recommended for all persons with cirrhosis and HBV or HCV infection because the current evidence is only suggestive. Long-term randomized, controlled trials may provide definitive data; however, it will be difficult, if not impossible, to conduct such trials because of the improved efficacy of combination therapy with interferon and ribavirin in patients with chronic HCV infection and the development of new therapies for patients with HBV infection.
OBJECTIVE: To determine whether adolescent growth is associated with a decrease in flexibility. DESIGN: Longitudinal cohort study of urban high school students. MAIN OUTCOME MEASURES: Flexibility of hamstring muscles (popliteal angle), quadriceps muscles (quadriceps angle), lumbar extensor muscles (Schober test), and combined lower extremity-trunk muscles (Sit and Reach test). RESULTS: There was no relation between growth and changes in flexibility for the lumbar flexor muscles, hamstring muscles, or muscles involved in the Sit and Reach test. Although there was a slight decrease in flexibility of the quadriceps muscle with increases in growth, the very low r2adj value (0.01-0.06) strongly suggests that growth plays only a small role in determining the flexibility of individuals. CONCLUSION: These results strongly suggest that growth is not a cause of decreased flexibility during the peripubescent period.
OBJECTIVE: To evaluate the clinical and basic science evidence surrounding the hypothesis that stretching immediately before exercise prevents injury. DATA SOURCES AND SELECTION: MEDLINE was searched using MEDLINE subject headings (MeSH) and textwords for English- and French-language articles related to stretching and muscle injury. Additional references were reviewed from the bibliographies, and from citation searches on key articles. All articles related to stretching and injury or pathophysiology of muscle injury were reviewed. Clinical articles without a control group were excluded. RESULTS: Three (all prospective) of the four clinical articles that suggested stretching was beneficial included a cointervention of warm-up. The fourth study (cross-sectional) found stretching was associated with less groin/buttock problems in cyclists, but only in women. There were five studies suggesting no difference in injury rates between stretchers and nonstretchers (3 prospective, 2 cross-sectional) and three suggesting stretching was detrimental (all cross-sectional). The review of the basic science literature suggested five reasons why stretching before exercise would not prevent injuries. First, in animals, immobilization or heating-induced increases in muscle compliance cause tissues to rupture more easily. Second, stretching before exercise should have no effect for activities in which excessive muscle length is not an issue (e.g., jogging). Third, stretching won't affect muscle compliance during eccentric activity, when most strains are believed to occur. Fourth, stretching can produce damage at the cytoskeleton level. Fifth, stretching appears to mask muscle pain in humans. CONCLUSION: The basic science literature supports the epidemiologic evidence that stretching before exercise does not reduce the risk of injury.
BACKGROUND: Discrimination against gay, lesbian and bisexual (GLB) patients by physicians is well known. Discrimination against GLB physicians by their colleagues and superiors is also well known and includes harassment, denial of positions and refusal to refer patients to them. The purpose of this study was to identify and quantify the attitudes of patients toward GLB physicians. METHODS: Telephone interviews were conducted with 500 randomly selected people living in a large urban Canadian city. Subjects were asked if they would refuse to see a GLB family physician and, if so, to describe the reason why. They were then given a choice of 6 reasons obtained from consultation with 10 GLB people and 10 heterosexual people. RESULTS: Of the 500 subjects 346 (69.2%) were reached and agreed to participate. Of the 346 respondents 41 (11.8%) stated that they would refuse to see a GLB family physician. The 2 most common reasons for the discrimination (prevalence rate more than 50%) were that GLB physicians would be incompetent and the respondent would feel "uncomfortable" having a GLB physician. Although more male than female respondents discriminated against GLB physicians, the difference was not statistically significant. The proportion of male and female respondents who discriminated increased with age (p < 0.01). CONCLUSIONS: The observed prevalence of patient discrimination against GLB family physicians is significant. The results suggest that the discrimination is based on emotional reasons and is not related to such factors as misinformation about STDs and fear of being thought of sexually. Therefore, educational efforts should be directed against general perceptions of homosexuality rather than targeting specific medical concerns.
PURPOSE: To describe the knowledge and attitudes about confidentiality issues within family medicine teaching units (FMUs) at McGill University. METHOD: The authors surveyed McGill University FMU staff (physicians, nurses, and support staff) on their knowledge of and attitudes toward confidentiality issues. RESULTS: The response rate was 84%. Only one of nine questions on confidentiality laws was correctly answered by more than 80% of the respondents. Only 55% of the support staff knew that police are not permitted free access to charts, although the majority of those who answered incorrectly held attitudes that were consistent with the law. Only approximately 25% knew that physicians and nurses are not permitted free access to any medical record within the center. There were minimal differences between the professions or between the FMUs. CONCLUSION: These findings suggest that FMU staff do not fully understand their obligations towards patient confidentiality.
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OBJECTIVE: It is common practice to measure serum ferritin levels in endurance athletes because of the belief that low iron stores may compromise performance. The direct relationship between endurance performance and iron deficiency anemia is well known, but there are theoretical reasons to believe that endurance performance may be adversely affected by low iron stores even in the absence of frank anemia. The purpose of this article is to provide a critical review of the scientific evidence relating low iron stores to endurance performance. DATA SOURCES: Medline was searched using MeSH for articles related to ferritin and endurance published since 1985. Additional references were reviewed from the bibliographies of the retrieved articles. STUDY SELECTION: All clinical study designs were reviewed as well as relevant animal studies. Conclusions regarding endurance performance in humans were limited to data from clinical studies. DATA EXTRACTION AND SYNTHESIS: In reviewing the literature, the relative strengths of the study designs were examined carefully. Particular attention of the effectiveness of each study in isolating ferritin as the key independent variable. Dependent measures of endurance capacity were also evaluated. MAIN RESULTS: Eight studies isolated serum ferritin as the experimental variable. Only one study reported a significant improvement in endurance performance (time to exhaustion) in subjects with low ferritin levels treated with oral iron, but this finding may have been magnified by an unexplained decrease in time to exhaustion in the control group. Iron dosages differed in the studies reviewed. Two additional studies that reported increases in performance parameters following increases in ferritin were confounded by concomitant increases in hemoglobin levels. CONCLUSIONS: Iron supplementation can raise serum ferritin levels, but increases in ferritin concentration, unaccompanied by increases in hemoglobin concentration, have not been shown to increase endurance performance. Of concern to the clinician is that athletes with low ferritin levels but hemoglobin in the low-normal range may have iron deficiency anemia responsive to iron supplementation. Low ferritin with hemoglobin in the mid- to upper normal range is at best a relative indication for iron supplementation: low ferritin with hemoglobin in the low normal range is a stronger, yet still relative, indication for iron supplementation in athletes.