Investigating induced abortion in developing countries: methods and problems.

Interest in abortion research is reemerging, partly as a result of political changes and partly due to evidence of the contribution of induced abortion to maternal mortality in developing countries. Information is lacking on all aspects of induced abortion, particularly methodological issues. This article reviews the methodological dilemmas encountered in previous studies, which provide useful lessons for future research on induced abortion and its complications, including related deaths. Adverse health outcomes of induced abortion are emphasized, because these are largely avoidable with access to safe abortion services. The main sources of information are examined, and their relevance for assessing rates of induced abortion, complications, and mortality is addressed. Two of the major topics are the problems of identifying cases of induced abortion, abortion complications, and related deaths, and the difficulties of selecting a valid and representative sample of women having the outcome of interest, with an appropriate comparison group. The article concludes with a discussion of approaches for improving the accuracy, completeness, and representativeness of information on induced abortion. Although the prospects for high-quality information seem daunting, it is essential that methodological advances accompany program efforts to alleviate this important public health problem.     

Adverse effects of observational studies when examining adverse outcomes of drugs: case-control studies with low prevalence of exposure.

OBJECTIVES: The case-control study is commonly used to examine adverse drug events, in which prevalence of exposure in the source population is frequently very low. The objective of the current study was to examine the bias inherent in the odds ratio assessing the association between exposure and an adverse outcome when prevalence of exposure in the source population is extremely low. DESIGN: Monte Carlo simulations examined the effect of sample size, exposure prevalence, and magnitude of the underlying odds ratio on the bias of the estimated risk ratio, and the power to detect a non-zero risk ratio. RESULTS: Once the underlying odds ratio was at least four, the adverse effects of low prevalence of exposure was minimal. Studies with small sample sizes and low prevalence of exposure, coupled with small to moderate effect sizes, can result in biased estimates of association between exposure and disease status. With a sample size of 200 and an exposure prevalence of 0.5% in the control population, the bias in the estimated odds ratio can be as large as 115%. However, bias becomes negligible as sample size becomes large (n > or = 2000), even when prevalence of exposure is very low. Once the expected number of exposed controls is at least eight, the bias in the estimated odds ratio was no more than 5%. CONCLUSIONS: Studies with small sample sizes and low prevalence of exposure, coupled with small to moderate effect sizes can result in biased estimates of association between exposure status and adverse drug effects. However, bias becomes negligible as sample size becomes large.     

Association between ACE inhibitors and acute pancreatitis in the elderly

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitor-induced acute pancreatitis has been described in various case reports and drug surveillance databases. At present, no epidemiologic studies examining the potential association between ACE inhibitors and acute pancreatitis have been identified. OBJECTIVE: To determine whether there is an association between ACE inhibitor use and pancreatic events (acute pancreatitis, pancreatic surgery). METHODS: A retrospective cohort of Ontario residents aged >/=66 years was created using population-based administrative databases from January 1, 1994, through March 31, 2000. We compared the incidence of pancreatic events among new users of ACE inhibitors (study group), warfarin (null baseline group), and dihydropyridine calcium-channel antagonists (DCCAs; disease control group) using multivariate Cox proportional hazard models. OUTCOME MEASURES: The primary outcome measure was hospitalization with acute pancreatitis; the secondary outcome measure was incidence of pancreatic surgery. RESULTS: For acute pancreatitis, the crude incidence rates per 10,000 person-years were 9.0 for the ACE inhibitor group (n = 174,824); 7.1 for the DCCA group (n = 73,719), and 7.6 for the warfarin group (n = 40 057). Relative to warfarin users, neither ACE inhibitor users (adjusted rate ratio [aRR] = 1.35; 95% CI 0.94 to 1.93) nor DCCA users (aRR = 1.09; 95% CI 0.72 to 1.62) were at significantly higher risk of hospitalization for acute pancreatitis. For pancreatic surgery in the same population, the crude incidence rates per 10,000 person-years were 10.5 for the ACE inhibitor group, 10.6 for the DCCA group, and 10.7 for the warfarin group. Relative to subjects taking warfarin, neither ACE inhibitor users (aRR = 1.09; 95% CI 0.80 to 4.49) nor DCCA users (aRR = 1.11; 95% CI 0.79 to 1.56) were at significantly higher risk for pancreatic surgery. CONCLUSIONS: The use of ACE inhibitors does not appear to be associated with significant risk of acute pancreatitis among the elderly.     

The Relationship Between Body Image Perceptions and Condom Use Outcomes in a Sample of South African Emerging Adults

Prevention Science - HIV continues to be a health priority in South Africa. Consistent condom use helps prevent HIV, yet less than half of South African emerging adults use condoms consistently....     

Dihydropyridine calcium channel blockers and cardiovascular outcomes in elderly patients: a population-based study

BACKGROUND:

Dihydropyridine calcium channel blockers are widely used for the treatment of hypertension and angina. Despite safety concerns associated with short-acting agents, increasing evidence supports the safety of long-acting dihydropyridines. Although amlodipine is the best studied of these, there are few studies comparing it with nifedipine.

OBJECTIVE:

To examine the association between hospitalization for acute coronary syndromes and treatment with amlodipine or extended-release nifedipine in patients 65 years of age and older. The primary objective was a composite of hospital admission for angina or acute myocardial infarction.

METHODS:

The present population-based, retrospective cohort study used linked health care databases from Ontario. Propensity scores were used to identify highly similar patients started on amlodipine or extended-release nifedipine between April 1997 and March 2002. Time-to-event analysis was conducted using Cox proportional hazards models.

RESULTS:

The analysis included 24,190 patients (44% male; mean age 75 years) treated with amlodipine or extended-release nifedipine (n=12,095 each). The number of patients reaching the primary end point was 362 (3%) and 294 (2.4%) in the amlodipine and nifedipine groups, respectively. The groups were similar in a large number of demographic and clinical characteristics. No significant differences were observed among users of extended-release nifedipine (adjusted hazard ratio 0.91, 95% CI 0.74 to 1.13) relative to amlodipine.

CONCLUSIONS:

These findings suggest that amlodipine and extended-release nifedipine are not associated with differential rates of acute coronary events in older patients.     

Is ramipril really better than other angiotensin-converting enzyme inhibitors after acute myocardial infarction?

Whether angiotensin-converting enzyme (ACE) inhibitors are interchangeable and equally efficacious after acute myocardial infarction (AMI) is controversial. We assessed whether ramipril was superior to other ACE inhibitors after AMI as suggested by a previously published study. We performed a retrospective cohort study using linked administrative databases on >1.4 million elderly residents in the province of Ontario who were admitted to the hospital for AMI, survived >or=30 days after discharge, and were initiated on an ACE inhibitor after AMI and remained on the same ACE inhibitor from April 1, 1997 to March 31, 2000. We followed patients for 2 years and measured readmission for AMI or mortality, together or alone. Our cohort included 5,408 elderly patients. Compared with patients on enalapril, there was no significant difference for the combined end points of readmission for AMI or mortality across users of ramipril (adjusted hazard ratio 0.95, 95% confidence interval 0.79 to 1.15), lisinopril (adjusted hazard ratio 1.02, 95% confidence interval 0.84 to 1.25), or other ACE inhibitors (adjusted hazard ratio 1.08, 95% confidence interval 0.88, 1.32). In conclusion, the findings of this study support a class effect among ACE inhibitors in treatment after AMI.     

Use of angiotensin-converting enzyme inhibitor therapy and dose-related outcomes in older adults with new heart failure in the community

OBJECTIVE: To evaluate the dose-related benefit of angiotensin-converting enzyme (ACE) inhibitor therapy among older adults with heart failure and to evaluate whether low-dose ACE inhibitor therapy is better than none. DESIGN: Observational cohort study. SETTING: Community-dwelling older adults in Ontario, Canada. PATIENTS/PARTICIPANTS: We identified 16539 adults 66 years or older who survived 45 days following their first heart failure hospitalization discharge. MEASUREMENT AND MAIN RESULTS: Multivariate techniques including propensity scores were used to study the association between the dose of ACE inhibitor therapy dispensed and 3 outcomes: survival, survival or heart failure rehospitalization, and survival or all-cause hospitalization at 1 year of follow-up. Logistic regression models explored the association between initial dose dispensed and subsequent dose reduction or drug cessation. Overall, 10793 (65.3%) of patients were dispensed ACE inhibitor therapy, with more than a third (3935; 36.5%) initiated on low-dose therapy. Relative to dispensing of low-dose ACE inhibitor therapy, nonuse was associated with increased mortality (hazard ratio [HR], 1.12; 95% confidence interval [CI], 1.02 to 1.22). Dispensing medium-dose therapy provided a benefit similar to low-dose (HR, 0.94; CI, 0.86 to 1.03) and dispensing of high-dose therapy was associated with improved survival benefit (HR, 0.76; CI, 0.68 to 0.85). Relative to dispensing of low-dose ACE inhibitor therapy, dispensing high-dose conferred a benefit (HR, 0.87; CI, 0.80 to 0.95) on the composite outcome of 1-year mortality or heart failure hospitalization and the composite outcome of 1-year mortality or all-cause hospitalization (HR, 0.87; CI, 0.81 to 0.93). Relative to those dispensed low-dose ACE inhibitor therapy, those initially dispensed high-dose therapy were twice as likely to have their subsequent dose reduced or the therapy discontinued (odds ratio, 2.36; CI, 2.07 to 2.69). CONCLUSION: Our findings suggest that when possible, older adults should be titrated to the higher doses of ACE inhibitor therapy evaluated in clinical trials. If older adults cannot tolerate higher doses, then low-dose ACE inhibitor therapy is superior to none. High-dose ACE inhibitor therapy is not as well tolerated as lower doses.     

Drug-induced lithium toxicity in the elderly: a population-based study

Objectives: To study the association between hospital admission for lithium toxicity and the use of diuretics, angiotensin‐converting enzyme (ACE) inhibitors, and nonsteroidal antiinflammatory drugs (NSAIDs) in the elderly. Design: Population‐based nested case‐control study. Setting: Ontario, Canada. Participants: Ontario residents aged 66 and older treated with lithium. Measurements: Estimated relative risk of hospital admission for lithium toxicity. Results: From January 1992 to December 2001, 10,615 elderly patients continuously receiving lithium were identified, of whom 413 (3.9%) were admitted to the hospital at least once for lithium toxicity. After adjustment for potential confounders, a dramatically increased risk of lithium toxicity was seen within a month of initiating treatment with a loop diuretic (relative risk (RR)=5.5, 95% confidence interval (CI)=1.9–16.1) or an ACE inhibitor (RR=7.6, 95% CI=2.6–22.0). Conversely, neither thiazide diuretics nor NSAIDs were independently associated with a significantly increased risk of hospitalization for lithium toxicity. Conclusion: The use of loop diuretics or ACE inhibitors significantly increases the risk of hospitalization for lithium toxicity, particularly in naïve recipients.