Nancy A. Dreyer

Overall mortality of cellular telephone customers

Unlike mobile cellular telephones, in which the antenna is not part of the handset, a portable cellular telephone exposes the users head to radio frequency energy transmitted from the antenna. This exposure has prompted concerns about potential biological effects, including brain cancer. As a first step in a record-based mortality surveillance of cellular telephone customers, we report on overall mortality of a cohort of more than 250,000 portable and mobile telephone customers during 1994. We found age-specific rates to be similar for users of the two types of telephones. For customers with accounts at least 3 years old, the ratio of mortality rates in 1994 for portable telephone users, compared with mobile telephone users, was 0.86 (90% confidence interval = 0.47-1.53).

Utility of telephone company records for epidemiologic studies of cellular telephones.

We conducted a survey of over 5,000 telephone users who were customers of one large cellular telephone company covering four major geographical areas. Our primary goal was to assess the utility of ascertaining information on telephone use and type from telephone company records. We compared information from 3,949 respondents with corresponding data from company billing records. We found that 48% of the account holders were sole users, and 69% were the primary user, meaning that they accounted for at least 75% of the use. Respondent reports of amount of telephone use were highly correlated with data on the billing record (r = 0.74). Respondent reports of telephone type were similarly correlated with data from the manufacturer (r = 0.92). We also inquired about telephone holding patterns, since these have implications for exposure. Most users reported favoring one side of the head when using the telephone, but the side of the head used was not strongly associated with handedness.

Validity of claims-based definitions of left ventricular systolic dysfunction in Medicare patients

Ejection fraction (EF) is crucial information when studying the use and effectiveness of therapies in patients with heart failure (HF) and myocardial infarction (MI). We aimed to assess the validity of claims data‐based definitions of systolic dysfunction (SD).

Bromocriptine and puerperal seizures.

Case reports have prompted concern that the use of bromocriptine mesylate to prevent lactation in the puerperium increases the risk of postpartum seizure. We conducted a record-based case-control study of postpartum seizures in three data bases to evaluate this relation. We identified 43 women who had a postpartum seizure, and we matched 319 controls individually by hospital of delivery, quinquenium of age, and time of delivery. Overall, women taking bromocriptine had a 22% lower risk for seizures, that is, the relative risk estimate was 0.78, with a 90% confidence interval of 0.29 to 1.87. A reduction in seizure risk is consistent with reports of antiseizure activity for bromocriptine in various species, including humans. We found a small positive association between bromocriptine use and seizures occurring more than 72 hours after delivery, with a relative risk estimate of 1.6 after controlling for seizure history. This association was offset by a strong negative association between bromocriptine use and early-occurring seizures. The pattern of an initial reduced risk followed by an increase to normal or above-normal levels of risk could result from an antiseizure activity of bromocriptine, with a rebound in risk when bromocriptine is withdrawn.

Methods and Objectives of a Large US Multicenter Case-Control Study of Post-Transplant Lymphoproliferative Disorder in Renal Transplant Patients

A large multicenter case-control study is in progress in the United States, the primary goal of which is to provide information about the effects of specific immunosuppressants and other risk factors on posttransplant lymphoproliferative disorder (PTLD) in renal transplant patients. It will also provide incidence data and case characterization on PTLDs arising in a large contemporary population. Medical record data are being collected on up to 120 PTLD cases and up to four controls per case transplanted at 20 large US centers. Participants all received transplants on or after July 1, 1995 and PTLD cases will be identified through December 31, 2001. All cases undergo central clinical and pathologic review. Abstracted information includes detailed data (dosages, duration) on all immunosuppressants (induction, maintenance, anti-rejection) as well as antiviral treatment. Other data include demographics, transplant history, HLA matching and viral status (e.g., Epstein-Barr virus, cytomegalovirus). Information associated with the PTLD diagnosis and initial therapy for PTLD is also collected. To date, 86 potential cases have been reported. Twenty (24%) are pediatric patients (< or =18 years). Median time between transplant and PTLD is 268 days; 53 (62%) were diagnosed within the first year. Cumulative incidence through 1998 is 0.7% for adults and 4.5% for children. The most common single site for PTLD is the allograft. Common treatments included either a reduction or discontinuation of immunosuppression (90%) and antiviral treatment (66%). Overall, the allograft appears to be an important site of PTLD recurrence. Also, the incidence of renal PTLD since the introduction of new immunosuppressive therapies is similar to that reported earlier.

Making observational studies count: shaping the future of comparative effectiveness research.

There is substantial interest in using observational epidemiologic research in combination with randomized clinical trials (RCTs) and meta-analyses to support decisionmaking by regulators, payers, and physicians. Nevertheless, even well-designed and well-conducted observational studies are often viewed with skepticism. This lingering distrust comes, in part, from the well-accepted use of clinical trials compared with a widespread lack of familiarity with the principles for good conduct in observational research. The solution lies in sound guidelines for evaluating observational studies, especially studies that may prove useful for evaluating clinical effectiveness. Such guidance would help to focus on the quality and relevance of the evidence, whatever the study design. With ever more medical interventions available, the need for hard evidence about which treatments work best, for whom and when, is spurring big changes. These changes are embodied in 3 new laws in the United States, starting with the Food and Drug Administration Amendment Act of 2007, followed by the American Recovery and Reimbursement Act of 2009, and the Patient Protection and Affordable Care Act of 2010. All 3 laws encourage evidence-based research to inform therapeutic decisionmaking, and ensure that comparative effectiveness research, defined as “the conduct and synthesis of research comparing the benefits and harms of different interventions and strategies to prevent, diagnose, treat and monitor health conditions in ‘real world’ settings,” will be driving decisions about patient care and health insurance coverage. Noninterventional studies provide information that is infeasible or impossible to obtain elsewhere. Interest may lie in risks and benefits that extend far into the future, or in patients and real-world practices that are not well characterized, such as patient subgroups and health practitioner specialties. It may be impractical, too expensive, or politically unacceptable to do a randomized trial or other type of intervention study. Preparing for seasonal influenza is an example. With the threat of a global pandemic of potentially serious swine flu, it would have been politically unacceptable to deny vaccination to some, making observational studies the preferred approach for characterizing the effectiveness of this type of vaccine. For the highly lethal H5N1 (avian) strain of influenza, little is known about what treatments work since the disease is rare and outbreaks are unpredictable. A multicountry patient registry provided data that revealed a 51% reduction in the fatality rate for patients with laboratory-confirmed H5N1 infection who were treated promptly with oseltamivir. This reduction in mortality was smaller but

A cost density analysis of benign prostatic hyperplasia.

We assessed the frequency and cost of care for benign prostatic hyperplasia (BPH) among approximately 165,000 subscribers to Fallon Community Health Plan (FCHP), a group model health maintenance organization located in central Massachusetts. We computed rates of episodes of medical services for BPH using automated utilization files, and we estimated costs using Medicare reimbursement schedules and medication average wholesale prices. We identified 3919 men who visited a physician for BPH from January 1, 1991, until December 31, 1994, during which time they contributed 8336 person-years to the analysis. This population comprises approximately 12% of men at least 40 years old at FCHP. From 1991 to 1994, 696 (18%) men received terazosin, 219 (6%) men underwent a prostatectomy, and 41 (1%) men received finasteride. Men averaged 1.66 office visits per year to a physician for BPH. Most office visits (61%) were to a primary care physician, with 39% of the visits to a urologist. Among patients who received terazosin, the frequency of office visits increased slightly after receiving terazosin, from 2.14 to 2.62 visits per year. Among surgery patients, the frequency of visits declined after prostatectomy, from 6.31 visits per year to 1.67 visits. The individual annual cost rate for BPH care ranged from

Characterisation of Asthma Management in the Fallon Community Health Plan from 1988 to 1991

25.00 to

Leukemia among nuclear workers with protracted exposure to low-dose ionizing radiation

25,352.00, with an average of

Toxic shock syndrome, contraceptive methods, and vaginitis

364.00 per person and a median cost of