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ABSTRACT: The literature on the relationship between breast cancer mortality and postmenopausal oestrogen and combined oestrogen/progestin therapy is seemingly contradictory. This study explored survival after exposure to oestrogen or oestrogen plus progestin at or in the year prior to breast cancer diagnosis. Information on patients first diagnosed with invasive breast cancer between 1993 and 1998 was linked with outpatient pharmacy data from 1992 to 2000. Patients were classified according to use of oestrogen alone or oestrogen plus progestin at or in the year prior to diagnosis. Compared to nonusers, and adjusting for age at diagnosis, race/ethnicity, tumour size and grade, oestrogen receptor status, surgery status, and chemotherapy and hormone therapy for breast cancer treatment, oestrogen plus progestin users had lower all-cause mortality (stage I hazard ratio (HR) = 0.69, 95% confidence interval (CI)= 0.48-0.99; stage II HR = 0.53, 95% CI = 0.39-0.72) and breast cancer mortality (stage I HR = 0.52, 95% CI = 0.26-1.04; stage II HR = 0.69, 95% CI = 0.48-0.98). Oestrogen users experienced little or no survival benefit for all-cause mortality (stage I HR = 1.04, 95% CI = 0.77-1.42; stage II HR = 0.86, 95% CI = 0.65-1.14) or breast cancer mortality (stage I HR = 1.23, 95% CI 0.72-2.10; stage II HR = 1.01, 95% CI 0.72-1.41). Our findings suggest, relative to nonusers, a lower risk of death from all causes and from breast cancer in patients who were diagnosed with breast cancer while exposed to oestrogen plus progestin, but not in patients exposed to oestrogen only.
British Journal of Cancer 09/2005; 93(4):392-8. · 5.04 Impact Factor
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D B Petitti
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ABSTRACT: This paper reviews publications from January 1999 to March 2001 on reproductive health topics that were self-identified as meta-analysis or were indexed as meta-analysis in MEDLINE. It sought to assess whether tests of statistical heterogeneity were done, whether the results were reported, and how a finding of significance for a test of statistical heterogeneity was handled and the results interpreted. The review identified some concerns. Tests of statistical heterogeneity were not done universally even though virtually all writers on the topic emphasize their importance. Even when done, results of these tests were not universally reported. Although the consensus appears to be that heterogeneity tests are conservative for meta-analysis of studies and a probability value of 0.10 is preferred, many meta-analyses used the conventional value of 0.05 without providing a reason. The rationale for the choice of a random or fixed effects model was not generally evident. The review also provided some positive models and some recommendations for assessing, reporting and exploring heterogeneity are made considering these models and the published recommendations of experts.
Statistics in Medicine 01/2002; 20(23):3625-33. · 1.88 Impact Factor
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ABSTRACT: This case-control study sought to determine whether rehospitalisation for jaundice in newborns is associated with the length of hospital stay after birth and to identify risk factors for and outcomes of rehospitalisation for jaundice. It was carried out among women who delivered a normal, term infant vaginally at any of 10 medical centres from 1992 to 1994. Cases were infants rehospitalised with jaundice within 14 days of birth. Controls were randomly selected from normal, term infants delivered vaginally but not rehospitalised within 90 days of birth. Maternal medical records for pregnancy, labour and delivery care, records for all the birth hospitalisations, and rehospitalisations for the cases were abstracted. The length of birth hospitalisation did not differ between case and control infants, whether length was measured as a categorical variable or as a continuous measure (median = 22.8 h for cases and 23.3 h for controls, P = 0.931). Rehospitalisation for jaundice was associated with race/ethnicity, primiparity, preterm birth, breast feeding and suspicion of jaundice during the birth hospitalisation. None of the rehospitalised infants died, were diagnosed with kernicterus or required resuscitation. Attention to risks associated with jaundice rehospitalisation might reduce this undesirable, but not commonly severe, outcome.
Paediatric and Perinatal Epidemiology 11/2001; 15(4):352-8. · 2.31 Impact Factor
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New England Journal of Medicine 10/2000; 343(13):970; author reply 972. · 53.30 Impact Factor
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ABSTRACT: To assess the risk of myocardial infarction in users of post-menopausal hormone replacement therapy who are at high risk of coronary disease because of hypertension, diabetes mellitus, or smoking, we used data from a previously published case-control study of women 45-74 years. After adjustment for age, ethnicity, and education, the odds ratio for myocardial infarction in current users of hormone replacement therapy was 0.9 (95% confidence interval (CI) = 0.5-1.6) in women with no major coronary risk factors, 0.8 (95% CI = 0.5-1.8) in women with one risk factor, and 1.1 (95% CI = 0.5-2.2) in women with two risk factors.
Epidemiology 10/2000; 11(5):603-6. · 5.57 Impact Factor
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ABSTRACT: The use of intrapartum antibiotics to prevent early-onset group B streptococcal (EOGBS) infection has left pediatricians in a quandary about the appropriate evaluation and treatment of infants at risk for this infection. The aim of this study was to determine whether intrapartum antibiotic prophylaxis changed the constellation and timing of onset of clinical signs of group B streptococcal (GBS) infection in term infants.
We conducted a retrospective chart review of infants who had EOGBS infection and were born in Southern California Kaiser Permanente Hospitals from 1988 through 1996. Objective criteria were used to ascertain maternal risk of infection, intrapartum antibiotic prophylaxis, and onset of clinical signs of infection.
Three hundred nineteen infants with EOGBS sepsis, bacteremia, or clinically suspected infection were identified from a population of 277 912 live births. Of the 172 term infants with culture-positive infection who had clinical signs of infection, 95% exhibited them in the first 24 hours of life. All of the infants exposed to intrapartum antibiotics became ill within the first 24 hours of life.
Exposure to antibiotics during labor did not change the clinical spectrum of disease or the onset of clinical signs of infection within 24 hours of birth for term infants with EOGBS infection. A 48-hour stay is not required to monitor asymptomatic term infants exposed to intrapartum antibiotics for onset of GBS infection.
Pediatrics 09/2000; 106(2 Pt 1):244-50. · 5.44 Impact Factor
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ABSTRACT: We evaluated a program of performance measurement and monitoring by assessing care process, utilization of services, and outcomes.
Information on 63,264 diabetic individuals who were continuously enrolled as members of Kaiser Permanente Southern California from 1 January 1994 to 31 December 1997 was used to evaluate the program. Time trends in testing for glycemic test and control and screening for dyslipidemia, use of lipid-lowering drugs, and microalbuminuria were evaluated as measures of care process. Time trends in hospitalization, outpatient appointments, prescriptions, and laboratory tests were evaluated as measures of utilization. Outcomes were hospitalization for myocardial infarction, ischemic stroke, and lower-limb amputation.
Between 1994 and 1997, improvements were evident in the process measures. The mean number of hospitalizations and the mean and median number of outpatients visits did not change. The mean number of laboratory tests increased from 13.2 in 1994 to 23.6 in 1997. The mean number of prescriptions for any medication increased from 19.7 to 24.3. Hospitalization rates for myocardial infarction did not change, but rates increased for ischemic stroke and lower-limb amputation.
Our findings suggest that measurement and monitoring of clinical performance can bring about modest improvements in measures of the processes of care in the absence of financial incentives, centrally driven interventions, and specialty care for all patients. In our setting, process improvements were associated with higher utilization of laboratory services and more prescriptions without an immediate return in terms of lower hospital utilization.
Diabetes Care 03/2000; 23(2):192-6. · 8.09 Impact Factor
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ABSTRACT: Reliable measurement of folate is becoming increasingly important as links between dietary folate intake, the use of vitamins containing folic acid, and health outcomes such as birth defects and cardiovascular disease are identified. This study was undertaken to formally assess whether the quantity of folate in serum declines after the serum is frozen and stored. Blood samples from 83 pregnant women were tested for serum folate shortly after collection and again after 18 days of storage at -20 degrees C. A shift from higher to lower serum folate categories was observed after 18 days of storage. For the first test, 40.9 % of the samples were > or = 20 microg/L compared with 19.3 % of the test results on second test. For the 75 samples in the quantifiable range (< 40 microg/L), a mean decrease of 5.0 microg/L (+/- 0.5) of serum folate was observed (p < 0.0001). When compared to serum samples stored in a non frost-free freezer at -20 degrees C or -70 degrees C, serum stored in a frost-free freezer at -20 degrees C for even a short period of time may be relatively unstable and sensitive to minor temperature fluctuations associated with the freeze-thaw cycles.
Clinical laboratory 01/2000; 46(9-10):483-6. · 0.90 Impact Factor
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ABSTRACT: To measure patient satisfaction with pregnancy and newborn care.
To develop our survey, we reviewed domains of care that had been identified by national groups working to develop measures of satisfaction with care. Within these domains of care, items pertinent to pregnancy and newborn care were written, reviewed, and pilot tested in focus groups of women who had recently delivered a baby. A 24-item survey instrument was the result of this process.
We sent our survey to 2337 female members of the Southern California Kaiser Permanente Medical Care Program approximately 8 weeks after they had delivered a baby. The demographic and clinical characteristics of the respondents were compared with those of the nonrespondents.
A total of 1017 women (44%) completed and returned the survey. Eighty-eight percent of the women who responded were very or somewhat satisfied with the care they received during their pregnancy and the newborn period. Women who responded differed from those who did not respond on infant birthweight, maternal age and education, and other variables. The results of our survey were forwarded to local quality managers and physicians.
Satisfaction with care is an important measure of quality of care. Many changes in the delivery system were made in response to the information provided by survey respondents, including offering alternative appointment times and scheduling postpartum appointments before hospital discharge. Our survey instrument, which assesses satisfaction with pregnancy and newborn care, might be useful for other health maintenance organizations for identifying areas where improvement in care is needed.
The American journal of managed care 12/1999; 5(11):1407-13. · 2.46 Impact Factor
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ABSTRACT: From 1994 to 1998, median serum folate values in clinical specimens increased from 12.6 to 18.7 microg/L. The percentage of low values decreased. Food fortification with folic acid is a likely explanation.
The Lancet 10/1999; 354(9182):915-6. · 38.28 Impact Factor
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ABSTRACT: Regional practice-based network research has grown significantly in the past 15 years. Previous studies have reported on characteristics of physicians who participate in network research, but little is known about the specific a priori research interests of practicing physicians. Knowledge of such interests could be useful in planning network research studies. We conducted a mail survey to assess the research interests of primary care physicians in two contiguous research networks at the University of California at San Francisco (UCSF) and at Stanford University. Among 120 respondents from the UCSF Collaborative Research Network and 85 from the Stanford Ambulatory Research Network, the most common topics of interest were disease prevention, communication and compliance, and managed care. Among specific conditions, heart disease, hypertension, and respiratory infection were of interest to the majority of respondents. Topics not of interest to network members were obstetrics, diagnostic procedures, alcoholism, drug abuse, tuberculosis, male genito-urinary problems, occupational hazards, domestic violence, and AIDS and HIV. Identification of network physician research interests can help focus research and recruitment efforts on topics of interest and provide estimates of participation levels for planning studies and preparing funding applications for research networks.
Western Journal of Medicine 02/1999; 170(1):19-24.
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ABSTRACT: Study objective: To test the hypothesis that interfacility transfer is not associated with increased mortality, duration of stay, or readmission within 7 days.
We matched 3,298 patients who were hospitalized for chest pain or related complaints in Kaiser Permanente medical centers after transfer from the emergency department of a nonplan hospital (transported patients) with 3,298 patients of the same gender and age (+/-5 years) and with the same principal diagnosis who were hospitalized within 6 months without transfer in the same Kaiser Permanente medical center (directly admitted patients). Patients were compared in terms of outcome measures: in-hospital deaths, continued care in another facility, readmission within 7 days, in-patient length of stay (LOS), and LOS in special care units.
The adjusted odds ratios for in-hospital mortality and readmission within 7 days were 1.0 (95% confidence interval,.8 to 1.4) and.9 (95% confidence interval,.7 to 1.2), respectively. The adjusted mean difference in LOS was -.1 days (95% confidence interval, -.2 to.1). Transported and directly admitted cardiac patients were also compared for all examined outcome measures at each of 10 medical centers. At a few medical centers, we observed significant difference in LOS, special care LOS, and continued care in another facility. However, all these differences were small, and most were probably random errors.
Conservative patient selection criteria, pretransfer stabilization, and the use of appropriate equipment and medical personnel have resulted in the interfacility transfer program's achieving its goal of transferring high-risk patients without adverse impact on clinical outcomes or resource use.
Annals of Emergency Medicine 02/1999; 33(1):33-43. · 4.13 Impact Factor
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ABSTRACT: The association of cocaine and amphetamine use with hemorrhagic and ischemic stroke is based almost solely on data from case series. The limited number of epidemiologic studies of stroke and use of cocaine and/or amphetamine have been done in settings that serve mostly the poor and/or minorities. This case-control study was conducted in the defined population comprising members of Kaiser Permanente of Northern and Southern California. We attempted to identify all incident strokes in women ages 15-44 years during a 3-year period using hospital admission and discharge records, emergency department logs, and payment requests for out-of-plan hospitalizations. We selected controls, matched on age and facility of usual care, at random from healthy members of the health plan. We obtained information in face-to-face interviews. There were 347 confirmed stroke cases and 1,021 controls. The univariate matched odds ratio for stroke in women who admitted to using cocaine and/or amphetamine was 8.5 (95% confidence interval = 3.6-20.0). After further adjustment for potential confounders, the odds ratio in women who reported using cocaine and/or amphetamine was 7.0 (95% confidence interval = 2.8-17.9). The use of cocaine and/or amphetamine is a strong risk factor for stroke in this socioeconomically heterogeneous, insured urban population.
Epidemiology 12/1998; 9(6):596-600. · 5.57 Impact Factor
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ABSTRACT: The available data on low-dose oral contraceptive pill (OCP) use and stroke risk in US women are limited by small numbers. We sought more precise estimates by conducting a pooled analysis of data from 2 US population-based case-control studies.
We analyzed interview data from 175 ischemic stroke cases, 198 hemorrhagic stroke cases, and 1191 control subjects 18 to 44 years of age.
For ischemic stroke, the pooled odds ratio (pOR) adjusted for stroke risk factors for current use of low-dose OCPs compared with women who had never used OCP (never users) was 0.66 (95% confidence interval [CI], 0.29 to 1.47) and compared with women not currently using OCPs (nonusers) the pOR was 1.09 (95% CI, 0.54 to 2.21). For hemorrhagic stroke, the pOR for current use of low-dose OCPs compared with never users was 0.95 (95% CI, 0.46 to 1.93) and compared with nonusers the pOR was 1.11 (95% CI, 0.61 to 2.01). The pORs for current low-dose OCP use and either stroke type were not elevated among women who were >/=35 years, cigarette smokers, obese, or not receiving medical therapy for hypertension. pORs for current low-dose OCP use were 2.08 (95% CI, 1. 19 to 3.65) for ischemic stroke and 2.15 (95% CI, 0.85 to 5.45) for hemorrhagic stroke among women reporting a history of migraine but were not elevated among women without such a history. Past OCP use (irrespective of formulation) was inversely related to ischemic stroke but unrelated to hemorrhagic stroke.
Women who use low-dose OCPs are, in the aggregate, not at increased risk of stroke. Studies are needed to clarify the risk of stroke among users who may be susceptible on the basis of age, smoking, obesity, hypertension, or migraine history.
Stroke 11/1998; 29(11):2277-84. · 5.73 Impact Factor
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ABSTRACT: Population-based case-control studies to assess the relationship of low-dose oral contraceptive (OC) use with myocardial infarction (MI) were performed at 2 sites in the United States (California and Washington state). The purpose of the present study was to estimate risk of MI in relation to use of low-dose OCs in a pooled analysis combining results from the 2 sites.
The study included as cases women aged 18 to 44 years with incident MI who had no prior history of ischemic heart disease or cerebrovascular disease. Women in the case and control groups were interviewed in person regarding OC use and cardiovascular risk factors. The analysis included 271 MI cases and 993 controls. Compared with noncurrent users, the adjusted pooled odds ratio for MI in current OC users was 0.94 (95% CI, 0.44, 2.20) after adjustment for major risk factors and sociodemographic factors. Compared with never users, the adjusted pooled odds ratio for MI was 0.56 (0.21, 1.49) in current OC users and 0.54 (0.31, 0.95) in past OC users. Among past OC users, duration and recency of use were unrelated to MI risk as was current hormone replacement therapy. There was no evidence of interaction between OC use and age, presence of cardiovascular risk factors (hypercholesterolemia, hypertension, diabetes), obesity, or smoking.
We conclude that low-dose OCs as used in these populations are safe with respect to risk of MI in women.
Circulation 10/1998; 98(11):1058-63. · 14.74 Impact Factor
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ABSTRACT: A 1995 publication on serious adverse events in users of Norplant implants submitted to the Food and Drug Administration's MedWatch Spontaneous Reporting System reported 14 hospitalizations for stroke in Norplant users. This number was higher than expected. This is a report on the association of current use of Norplant implants with stroke and myocardial infarction (MI) based on a pooled analysis of data from two population-based, case-control studies conducted in the US. All data collection for these two studies occurred after approval of Norplant implants for marketing in the US in December 1990. The methods of the individual studies are detailed in prior publications.
Contraception 06/1998; 57(5):361-2. · 2.72 Impact Factor
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ABSTRACT: Epidemiologic studies of current oral contraceptive (OC) use and myocardial infarction (MI) have been contradictory and confusing. This comprehensive review of the epidemiologic literature attempts to draw conclusions about the risk of myocardial infarction in oral contraceptive users, focusing on recent, methodologically rigorous studies of the topic. Recent studies are consistent in showing a higher relative risk of MI in current OC users who smoke compared with current OC users who do not smoke. Studies in aggregate suggest that the relative risk of MI is higher in current OC users with hypertension than in current OC users without hypertension. Recent studies do not show a relationship between higher estrogen dose and higher risk of MI, but the effect of estrogen dose and progestogen type and dose are difficult to separate. The limited data on the risk of MI in current users of low estrogen OC do not allow a firm conclusion about the possibility that progestogen type might affect the risk of MI in current users. Past OC use does not increase or decrease the risk of MI.
Contraception 04/1998; 57(3):143-55. · 2.72 Impact Factor
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ABSTRACT: Information about the risk of stroke in current postmenopausal hormone users is limited.
In this case-control study, women aged 45 to 74 years hospitalized with a fatal or nonfatal stroke in any of 10 Northern California Kaiser Permanente facilities during the period November 1991 to November 1994 were identified as cases. Controls were selected at random from female Health Plan members. Data regarding use of estrogen plus progestogen or estrogen alone were obtained in interviews.
The analysis was based on nonproxy responses from 349 cases of ischemic stroke and 349 matched control subjects. After adjustment for confounders, the odds ratio for ischemic stroke in current hormone users was 1.03 (95% confidence interval, 0.65 to 1.65). The odds ratios for ischemic stroke in current hormone users showed no clear trend of increasing or decreasing risk in relation to duration of hormone use. The odds ratio for ischemic stroke in past hormone users was 0.84 (95% confidence interval, 0.54 to 1.32).
In this study postmenopausal hormone use was not associated with an increase or decrease in the risk of ischemic stroke, a finding that is consistent with the body of literature on this topic.
Stroke 02/1998; 29(1):23-8. · 5.73 Impact Factor
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ABSTRACT: To estimate the relative risk for incident acute myocardial infarction in relation to the current use of estrogen and estrogen-progestogen.
Retrospective case-control study.
Medical centers of a large prepaid health care program, the Kaiser Permanente Medical Care Program (KPMCP), Northern California region.
All women hospitalized at a KPMCP center for incident acute myocardial infarction during a 3-year period from 1991 to 1994. Controls were matched to case-patients for year of birth and KPMCP facility and were selected at random from among all female members of the KPMCP.
An in-person interview that included questions about current and lifetime use of estrogen and estrogen-progestogen; known cardiovascular risk factors; and other medical, sociodemographic and behavioral factors that might affect risk for myocardial infarction.
Odds ratios for myocardial infarction associated with use of estrogen and estrogen-progestogen.
The odds ratio for myocardial infarction in current users of estrogen or estrogen-progestogen compared with women who had never used these agents was 0.96 (95% CI, 0.66 to 1.40) after adjustment for confounders. The odds ratio for myocardial infarction in past users of estrogen or estrogen-progestogen was 1.07 (CI, 0.72 to 1.58). Duration of hormone use was unrelated to the odds ratio for myocardial infarction.
This study did not show a statistically significant decrease in the odds ratio for myocardial infarction associated with current use of estrogen or estrogen-progestogen. It neither confirms nor refutes the hypothesis that hormone use prevents myocardial infarction in postmenopausal women.
Annals of internal medicine 11/1997; 127(7):501-8. · 16.73 Impact Factor
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D B Petitti
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ABSTRACT: It is likely that more studies that use meta-analysis will be published in the endocrinologic literature. Major strengths of meta-analysis are the systematic ascertainment of research on a given topic and the explicit delineation of reasons for accepting or rejecting studies as a basis for drawing conclusions. The tendency of meta-analysis to focus on a single estimate of effect and to ignore heterogeneity are problems both with the conduct of meta-analysis and the way in which it is interpreted. Meta-analysis cannot overcome bias in the original studies. It is difficult to perform a good meta-analysis and easy to perform a bad one. The critical reader should not be overawed by the results of a meta-analysis. Reading a meta-analysis should not substitute for careful reading of the primary studies on which the meta-analysis is based. Meta-analysis should not be used to stifle the conduct of original research.
Endocrinology & Metabolism Clinics of North America 04/1997; 26(1):31-44. · 3.41 Impact Factor
