Guidelines for Good Epidemiology Practices for drug, device, and vaccine research in the United States.
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Journal Article↗
Biomedical subjects
A Stergachis
Publications and source records attributed to A Stergachis.
Current use of thiazide diuretics and prevention of femur fractures.
A case control study of a defined population from The Netherlands was performed to evaluate the risk of femur fractures associated with the use of thiazide diuretics. Included were 386 patients hospitalized for femur fractures between 1986 and 1990 who were residents and 45 years of age and older. Per case, one age-, sex-, pharmacy-, and general practitioner-matched control was chosen from the general population. Drug use was ascertained from computerized pharmacy records. The adjusted odds ratio of current use of thiazide diuretics was 0.5 (95% confidence interval, 0.3-0.9). The protective effect of thiazide diuretics was greatest for use of 1 year or longer at relatively high doses of thiazides (odds ratio, 0.3; 95% confidence interval, 0.1-0.9). We also found that patients who discontinued thiazide use longer than 2 months were not protected against femur fractures. These results support the hypothesis that use of thiazide diuretics protects against femur fractures.
Aged↗
Contraceptive methods and the risk of Chlamydia trachomatis infection in young women.
To evaluate the relation between contraceptive methods and cervical Chlamydia trachomatis infection, the authors studied a population-based sample of 1,779 nonpregnant women aged 15-34 years who underwent cell culture diagnostic testing for the detection of C. trachomatis at a health maintenance organization. Barrier contraceptive method users were classified as those who reported using one of the following methods at time of testing: condom, diaphragm, cervical cap, spermicidal sponge, foam, or vaginal spermicidal suppositories. Barrier methods were associated with a reduction in the risk of chlamydial infection in women aged 25 years or older when compared with all other women in the same age category (adjusted prevalence odds ratio = 0.15, 95% confidence interval (CI) 0.04-0.66). When compared with only noncontracepting women, the adjusted prevalence odds ratio was 0.34 (95% CI 0.06-1.99). The protective effect of barrier methods was not evident in women younger than age 25 years. Oral contraceptive use was not associated with the risk of C. trachomatis infection using either referent group; the adjusted prevalence odds ratio was 0.99 (95% CI 0.57-1.73) compared with all other women, and 0.88 (95% CI 0.44-1.79) compared with noncontracepting women. These findings suggest that present patterns of use of barrier methods differ by age and afford only selective protection against cervical C. trachomatis infections.
Adolescent↗
Nonsteroidal antiinflammatory drug discontinuation in patients with osteoarthritis.
OBJECTIVE: To determine whether discontinuation patterns differed among nonsteroidal antiinflammatory drugs (NSAID) prescribed to treat osteoarthritis (OA). METHODS: In a retrospective cohort study of Health Maintenance Organization enrollees, 1405 patients with OA aged 45 and older who received a new prescription for one of 4 NSAID were followed for 12 months. Survival analysis was used to evaluate time to discontinuation, used here as a relative measure of both drug efficacy and tolerability. RESULTS: Rates of NSAID discontinuation during the study period were high; only 15 to 20% of those started on a study NSAID were still using the same drug at the end of the 12 month followup period. Using a proportional hazards model to adjust for covariates, the risk of discontinuation did not differ when comparing the agent with the longest duration of use, piroxicam (the referent), to enteric coated aspirin [relative risk (RR) 1.10, 95% confidence interval (CI) 0.93 to 1.30]. Adjusted rates of discontinuation were significantly higher for ibuprofen (RR 1.43, 95% CI 1.22 to 1.69) and for naproxen (RR 1.40, 95% CI 1.19 to 1.65) when compared to piroxicam. CONCLUSION: NSAID discontinuation rates are high among patients with OA and risk of discontinuation differed between NSAID, even after controlling for the effects of such variables as age, disease severity, and concomitant therapy.
Aged↗
Postmenopausal estrogen replacement therapy and the risk of Alzheimer's disease: a population-based case-control study.
Preliminary animal and human data suggest that estrogens may be protective against Alzheimer's disease in women. In a population-based case-control study at Group Health Cooperative of Puget Sound, Seattle, Washington, the authors compared the exposure of estrogen replacement therapy of 107 female Alzheimer's disease cases with 120 age- and sex-matched controls by using computerized pharmacy data. The cases were obtained from the Alzheimer's Disease Patient Registry of the University of Washington, Seattle, Washington, which is based on the enumerated health plan population from 1987 to 1992. Newly recognized cases of probable Alzheimer's disease according to standardized diagnostic criteria were ascertained, evaluated, and enrolled in the Registry. The controls were selected from the same defined population by stratified random sampling. When the authors applied logistic regression, ever use of estrogens did not show an association with Alzheimer's disease (adjusted odds ratio = 1.1, 95 percent confidence interval 0.6-1.8). Oral and vaginal estrogens yielded similar results. In conclusion, this study provides no evidence that estrogen replacement therapy has an impact on the risk of Alzheimer's disease in women.
Administration, Intravaginal↗
Cigarette smoking and functional ovarian cysts.
This population-based case-control study assessed the effect of current cigarette smoking on the risk of functional ovarian cyst development. Cases were all 15-39 year-old enrollees of Group Health Cooperative of Puget Sound (GHC) who had either an inpatient primary diagnosis of functional ovarian cyst in 1988 or 1989 (n = 61) or an outpatient primary diagnosis of functional ovarian cyst at five GHC primary care clinics (n = 37). Controls were randomly selected enrollees matched to cases on age, primary care clinic, and enrollment date (n = 239). A total of 36.7% of cases and 20.5% of controls were determined by medical record review to be current smokers. Compared with women who were not current smokers, the relative risk of a diagnosed functional ovarian cyst among smokers was 2.0 (95% confidence interval 1.1-3.5). This finding, in an area of little previous research, provides a promising lead in the investigation of the etiology of functional ovarian cysts and the effects of smoking on ovarian function in general.
Adolescent↗
Accuracy of technicians and pharmacists in identifying dispensing errors.
The accuracies with which pharmacists and technicians checked medications in a unit dose distribution system were compared. The study was conducted at three large hospitals in Washington State. From August through October 1991, technicians filled unit dose medication drawers and pharmacists verified the accuracy of each fill (pharmacist verification period). From November 1991 through January 1992, technicians who had undergone special training verified the accuracy with which medication drawers were filled by other technicians (technician verification period). For each study period, two error rates were estimated: the frequency with which the pharmacists or technicians identified dispensing errors and the frequency of verification errors identified by the investigators in a final independent check. A total of 143,952 unit doses were dispensed during the pharmacist verification period, of which 49,718 were randomly analyzed for accuracy. A total of 151,721 doses were dispensed during the technician intervention period, of which 55,470 were assessed. The mean +/- S.E. daily rates of dispensing-error identification by pharmacists (0.0125 +/- 0.0069%) and technicians (0.0119 +/- 0.0001) did not differ significantly. While pharmacists overlooked more errors (107) than technicians (50), the percentage of such missed errors classified as potentially serious did not differ significantly between the groups (25.2% versus 32.0%, respectively). Pharmacy technicians who underwent special training were able to verify medications in a unit dose distribution system without compromising the accuracy of dispensing.
Education, Pharmacy↗
Cost-effectiveness of unenhanced MR imaging vs contrast-enhanced CT of the abdomen or pelvis.
OBJECTIVE: The purpose of this study was to compare the cost of unenhanced MR imaging with that of CT with high- or low-osmolality contrast agents for abdominal or pelvic imaging in patients at risk for nephrotoxic effects induced by contrast material. MATERIALS AND METHODS: Using decision analysis, we evaluated direct medical care costs associated with the use of CT with high- or low-osmolality contrast agents vs MR imaging. We used data from a variety of sources and assumed that the three imaging techniques provide nearly equivalent diagnostic information. The base-case analysis assumed that patients were at low risk (i.e., 2%) for development of nephrotoxic effects. Nephrotoxic effects were defined as increases in the serum level of creatinine of 50% or more above baseline. Our analysis took the perspective of the hospital and used estimated hospital costs, not charges. Sensitivity analyses were performed on risk estimates for development of nephrotoxic effects and for the estimates of medical care costs. RESULTS: For the base case, CT with a high-osmolality contrast agent is the least costly imaging strategy. When the risk of nephrotoxic effects exceeds 5% for high-osmolality contrast agents or 2.6% for low-osmolality contrast agents, then MR imaging is the preferred strategy. The model is relatively insensitive to treatment costs. CONCLUSION: From a hospital's perspective, MR imaging of the abdomen or pelvis is cost minimizing in patients at high risk for nephrotoxic effects induced by contrast agents. Use of low-osmolality contrast agents must reduce the frequency of nephrotoxic effects in high-risk patients by at least 50% to be less costly than MR imaging.
Abdomen↗
Selective screening for Chlamydia trachomatis infection in a primary care population of women.
The authors used cell cultures to assess the prevalence of cervical infection caused by Chlamydia trachomatis in a population-based sample of nonpregnant women aged 15 to 34 years who attended two primary care clinics at Group Health Cooperative of Puget Sound, Seattle, Washington, between January 1, 1988, and June 30, 1989. C. trachomatis was isolated from 67 of 1,804 women (3.7%), including 13% of those who were less than 20 years of age. Seven patient characteristics were independently predictive of chlamydial infection by stepwise multivariate logistic regression analysis: being unmarried, examination showing cervical ectopy, black race, douching, nulliparity, age of 24 years or less, and intercourse with two or more partners within the preceding year. Testing all women who had a score of 5 or more (28% of women) on a weighted index based on risk factors would detect 77% of all infections with a positive predictive value of 9%. These results suggest that it should be feasible to develop a risk factor-based program to screen for cervical infection with C. trachomatis in populations where its prevalence is low.
Adolescent↗
Vaginal douching as a risk factor for acute pelvic inflammatory disease.
OBJECTIVE: To conduct a population-based evaluation of vaginal douching as a risk factor for acute pelvic inflammatory disease (PID), emphasizing timing, frequency, and reasons for douching. METHODS: A population-based case-control study was conducted at Group Health Cooperative of Puget Sound, a staff-model health maintenance organization located in western Washington state. The cases (N = 131) were women 18-40 years of age who experienced a first episode of clinically diagnosed acute PID. Both hospitalized and ambulatory-care patients were identified. Medical records were reviewed for clinical inclusion criteria and for additional evidence of inflammation/infection. Controls (N = 294) were chosen from a population-based series of randomly selected women from a concurrent Group Health study of ectopic pregnancy. Of the women identified, 72.4% of cases and 73.4% of controls agreed to participate. RESULTS: Relative to women who reported never having douched, women who douched during the previous 3 months had a risk of PID of 2.1 after controlling for other measured risk factors (95% confidence interval [CI] 1.2-3.9). Women who douched at least once a week had a higher estimated risk (odds ratio 3.9, 95% CI 1.4-10.9) than those who douched less often (odds ratio 1.8, 95% CI 1.0-3.4). The risk was highest in the small group of women who gave infection as the reason for douching (odds ratio 7.9, 95% CI 2.6-24.2). However, exclusion of this group did not eliminate the association among the remaining women (odds ratio 3.0, 95% CI 1.0-9.1 for douching at least once a week). CONCLUSION: These population-based data lend added support to the hypothesis that vaginal douching can predispose a woman to PID.
Acute Disease↗
Tubal sterilization and risk of subsequent hospital admission for menstrual disorders.
OBJECTIVE: Our objective was to investigate tubal sterilization and subsequent hospitalization for menstrual disorders. STUDY DESIGN: Automated discharge data were used in a population-based cohort study of 7253 women aged 20 to 49 years with tubal sterilization (1968 through 1983) at Group Health Cooperative of Puget Sound. Comparisons were with an age-matched cohort of 25,448 nonsterilized women and a nonmatched cohort of 5283 spouses of men with vasectomies. RESULTS: In the sterilization cohort, 282 had hospitalization for menstrual disorders (curettage, n = 191; hysterectomy, n = 66; nonsurgical, n = 25). Risk of hospitalization for menstrual disorders was 2.4 times greater after tubal sterilization (95% confidence interval 2.0 to 2.9). This risk was 6.1 times greater for sterilized women aged 20 to 24 years (95% confidence interval 0.72 to 3.2). Compared with the risk for nonsterilized women whose spouses had a vasectomy, the risk was 1.6 times greater (95% confidence interval 1.3 to 2.1). Hospitalization for menstrual disorders was not more common after unipolar sterilization than after other methods, as might have been expected if the menstrual disorder was related to impaired uteroovarian circulation. CONCLUSIONS: Tubal sterilization is associated with a greater risk of hospitalization for menstrual disorders. A biologic association is not supported by these results.
Cohort Studies↗
Epidemiology of the noncontraceptive effects of oral contraceptives.
Epidemiologic studies have made major contributions to our understanding of oral contraceptive safety. The findings of major studies of the risk of cardiovascular disease and neoplasia associated with oral contraceptive use are reviewed, with discussion of the many factors to be considered in the interpretation of conflicting results. Mortality data that were based on earlier oral contraceptive formulations, dosage, and usage patterns may not be relevant to current practices. Recent studies suggest that reduced doses of estrogens and progestins in current oral contraceptive formulations and better screening of patients have reduced the risks of cardiovascular disease associated with oral contraceptive use, with the most important exception being an increased risk among older women who smoke. While most epidemiologic studies demonstrate no overall association between oral contraceptives and breast cancer, unanswered questions remain concerning this relationship.
Cardiovascular Diseases↗
Functional ovarian cysts in relation to the use of monophasic and triphasic oral contraceptives.
This population-based case-control study assessed the effect of current use of monophasic or triphasic oral contraceptives (OCs) on the risk of functional ovarian cyst development. The cases were all 15-39-year-old enrollees in the Group Health Cooperative of Puget Sound who had either an inpatient primary diagnosis of functional ovarian cyst in 1988 or 1989 (N = 67) or an outpatient primary diagnosis of functional ovarian cyst from March 1988 through August 1989 at one of five Group Health Cooperative primary care clinics (N = 39). Controls were randomly selected enrollees matched to the cases for age, primary care clinic, and enrollment date (N = 255). Subjects with previous hysterectomy or oophorectomy were excluded from this analysis. Pharmacy and medical record review showed that 16% of cases and 19% of controls were currently using monophasic OCs, whereas 11% of cases and 9% of controls were using triphasic OCs. Compared with women not using hormonal contraception, the relative risks of a diagnosed functional ovarian cyst among women currently using OCs were 0.8 (95% confidence interval [CI] 0.4-1.8) for users of monophasic OCs and 1.3 (95% CI 0.5-3.3) for users of triphasic OCs. In contrast to previous studies of monophasic OCs containing higher steroid dosages, the results of this study suggest that current use of low-dose monophasic OCs does not substantially decrease a woman's risk of functional ovarian cyst formation. In addition, our results do not support recent speculation that current use of triphasic OCs appreciably increases the risk of functional ovarian cysts.
Adult↗
Medical care and cost outcomes after pentoxifylline treatment for peripheral arterial disease.
We assessed the medical outcomes and costs associated with the pharmacologic treatment of patients with peripheral arterial disease (PAD) in a population-based historical cohort study of patients enrolled in a health maintenance organization. For up to 2 years, we compared 58 patients who used therapeutic amounts of pentoxifylline with a comparison group of 112 patients who received a minimal subefficacious trial of pentoxifylline. Medical records data were used to assess and control for the severity of PAD and other potentially confounding factors. Continuous use of a therapeutic amount of pentoxifylline during an initial 120-day period significantly reduced the incidence of PAD-related invasive therapeutic and diagnostic procedures in the first year of follow-up (adjusted relative risk, 0.35; 95% confidence interval, 0.12 to 0.99). However, there were no significant differences in the risk of a PAD-related hospitalization or cost of PAD-related care between continuous pentoxifylline users and the comparison group. Pentoxifylline therapy may reduce the risk of vascular surgery while not increasing the total cost of PAD care.
Aged↗
Diuretic drug use and the risk for hip fracture.
OBJECTIVE: To test the hypothesis that use of thiazide diuretics prevents hip fracture and to study the risk for hip fracture associated with furosemide use. DESIGN: A case-control study. SETTING: Hospitals owned by a health maintenance organization in Washington. PATIENTS: Elderly patients (n = 462) hospitalized because of a hip fracture between 1977 and 1983 and an equal number of age- and sex-matched population-based control patients. MEASUREMENTS: Use of thiazide diuretics and furosemide was ascertained from medical records and computerized pharmacy records. The relative risk for hip fracture associated with diuretic use was calculated and adjusted for the potentially confounding effects of nursing home residence; previous hospitalizations; a history of stroke, alcoholism, or the organic brain syndrome; body weight; leg paralysis; and use of phenobarbital, corticosteroids, or other diuretics. Current and former users of diuretics were analyzed separately. MAIN RESULTS: The adjusted risk for hip fracture was 1.6 (95% CI, 1.0 to 2.5) for current thiazide users. The adjusted risk for hip fracture for current furosemide use was 3.9 (CI, 1.5 to 10.4). CONCLUSIONS: According to this study, use of thiazide diuretics did not protect against hip fracture and cannot be recommended for fracture prevention. Current furosemide use was also associated with hip fracture.
Aged↗
Maternal cigarette smoking and the risk of tubal pregnancy.
The association between maternal smoking and the occurrence of tubal pregnancy was evaluated in a population-based case-control study of members of the Group Health Cooperative of Puget Sound, Seattle, Washington. Women hospitalized with tubal pregnancy from October 1981 through September 1986 (n = 274) were compared with reproductive-age women who were at risk of becoming pregnant during the same time period (n = 727). The relative risk of tubal pregnancy associated with ever having smoked cigarettes was 1.3 (95% confidence interval (CI) 1.0-1.8). Compared with women who had never smoked, those who smoked at the time of conception had a 40% increase in the risk of tubal pregnancy (95% CI 1.0-2.0). These results support earlier epidemiologic and nonepidemiologic reports of a greater risk of tubal pregnancy associated with current or recent maternal cigarette smoking.
Case-Control Studies↗
Vaginal douching and the risk of tubal pregnancy.
To explore the possible association between vaginal douching and tubal pregnancy, we interviewed 273 women who were diagnosed with tubal pregnancy at Group Health Cooperative between September 31, 1981 and October 1, 1986. Their responses were compared with responses of a random sample of 722 female members of Group Health Cooperative who were assumed to be at risk of becoming pregnant at the time the cases conceived. After adjusting for differences between cases and controls with regard to other measured risk factors, we found a modest increase in risk associated with having douched more than two times per year in the past (RR = 1.3, 95% CI: 0.9-1.8). Among women who had more than one sexual partner during their lifetime, however, the risk for those who had douched more than twice per year was somewhat higher (RR = 1.6, 95% CI: 1.1-2.3). There was an indication that women who had been exposed to Chlamydia trachomatis, as indicated by elevated antibody titers, may further increase their risk for tubal pregnancy by douching (RR = 2.4, 95% CI: 0.8-7.3). The associations found in other studies between douching and pelvic inflammatory disease, and between pelvic inflammatory disease and subsequent tubal pregnancy, argue that a relation between douching and tubal pregnancy might be anticipated. Our results offer further support for this hypothesis.
Adolescent↗
Results and effect of refusal recontact in a case-control study of ectopic pregnancy.
In a population-based study of ectopic pregnancy, a card-back system of initial subject contact yielded a positive response from 85.1% of potential cases and 65.0% of potential controls. We subsequently recontacted by telephone potential controls who had declined to participate and offered them $10 compensation for participation. We recontacted 205 of the 330 control women who had refused to participate. Twenty-eight were found to be ineligible, and 75.7% of the remaining 177 agreed to participate on recontact. The additional 125 women were not recontacted, 9 because of firm initial refusals and 116 because the study ended before contact could be sought or made. Controls who initially declined to participate but subsequently agreed differed from those who initially agreed on a number of demographic and reproductive characteristics, and estimates of ectopic pregnancy risk associated with induced abortion and tubal sterilization changed slightly with the inclusion of initial nonparticipants. We conclude that use of a card-back system of subject contact yields a low level of positive response among reproductive-aged women and that many initial nonparticipants can be converted into participants by personal contact and the offer of compensation.
Adult↗