B. Burt Gerstman

Intestinal Necrosis Associated With Postoperative Orally Administered Sodium Polystyrene Sulfonate in Sorbitol

We estimated the incidence of intestinal necrosis in 752 hospitalized patients who had received sodium polystyrene sulfonate (SPS). Of these 752 patients, 117 were exposed within 1 week of surgery. Two cases of intestinal necrosis were discovered, both in patients who had received orally administered SPS in sorbitol within 1 week of surgery. Based on these two cases, the postoperative incidence of intestinal necrosis associated with SPS was 1.8%. For comparative purposes, we identified 862 patients who had undergone hemodialysis, renal transplantation, or cardiac transplantation, but did not receive SPS. No cases of idiopathic intestinal necrosis were found in this second group (P = 0.014). These data suggest that SPS in sorbitol-associated intestinal complications may be a relatively common occurrence in postoperatively exposed patients.

Trends in the prevalence of asthma hospitalization in the 5- to 14-year-old Michigan Medicaid population, 1980 to 1986

BACKGROUND Despite advances in therapy, morbidity and mortality rates as a result of pediatric asthma appear to have increased during the past decade. Epidemiologic evidence suggests that these increases disproportionately affected black children and the urban poor. METHODS With use of data from the Medicaid Management Information System, we estimated the prevalence of asthma hospitalization in the 5- to 14-year-old Michigan Medicaid population for the period 1980 to 1986. RESULTS Large increases were seen between 1980 and 1984, with leveling off or a slight decline thereafter. In 5- to 9-year-old children, the prevalence of asthma hospitalization increased from 2.3 per 1000 persons in 1980 to 4.5 per 1000 in 1984. Ten- to 14-year-old children demonstrated an increase of 2.2 per 1000 in 1980 to 3.2 per 1000 in 1984. Comparable trends occurred in all strata defined by age, race, residency, and gender. However, the largest increases were noted in urban black children, in which the rate more than doubled from 3.2 per 1000 in 1980 to 7.1 per 1000 in 1984. The adjusted relative risk for asthma hospitalization associated with being male was 1.6 (95% CI: 1.5, 1.7), with being black was 2.2 (95% CI: 2.1, 2.4), and with living in an urban county was 1.1 (95% CI: 1.04, 1.4). CONCLUSIONS Within this relatively homogeneous low socioeconomic population, black race remained a strong predictor for asthma hospitalization, whereas urban residence was only minimally associated with this outcome.

Mortality resulting from blood dyscrasias in the United States, 1984

Blood dyscrasias are rare but serious diseases. We used national death certificate data for the year 1984 to estimate the number and rate of deaths caused by four blood dyscrasias. These diseases contributed to 4,490 deaths, corresponding to a mortality rate of 18.9 per million United States population. Aplastic anemia was the most frequent cause of death, followed by thrombocytopenia, agranulocytosis, and hemolytic anemia. Mortality rates varied by age, with a small peak in young children, lower rates for ages five through 34 years, and exponentially increasing rates beyond 35 years of age. Although drug relatedness could not be reliably ascertained from our data, other surveys have estimated that approximately 30% of fatal blood dyscrasias are caused by therapeutic drugs. Assuming that 30% drug attribution also applies to the U.S. population as a whole, approximately 1,350 blood dyscrasia deaths in the U.S. in 1984 may have been caused by drugs.

Interexaminer reliability of supine leg checks for discriminating leg-length inequality.

OBJECTIVE The purpose of this study was to quantify interexaminer reliability of a standardized supine leg check procedure used to screen for leg-length inequality. METHODS Two doctors of chiropractic used a standardized supine leg check procedure to examine 50 volunteers for leg-length inequality. The order of examination was randomized. The side and magnitude of leg-length inequality were determined to the nearest 1/8 in. Subjects and examiners were blinded. Interexaminer reliability was assessed with a Bland-Altman plot, tolerance table of absolute differences, a quadratic weighted κ statistic for quantitative scores, and a Gwets first-order agreement coefficient for dichotomous ratings. RESULTS The quadratic weighted κ statistic to quantify the reliability of the rating scale was 0.44 (95% confidence interval, 0.21-0.67), indicating moderate reliability. The 2 examiners agreed exactly 32% of the time, within 1/8 in 58% of the time, within 3/16 in 72% of the time, and within 3/8 in 92% of the time. The Bland-Altman plot revealed possible heterogeneity in reliability that requires additional study. The examiners agreed on the presence of a leg-length inequality of at least 1/8 in in 40 (80%) of 50 subjects (first-order agreement coefficient, 0.76), suggesting good agreement for this diagnostic category. CONCLUSION The examiners showed moderate reliability in assessing leg-length inequality at 1/8-in increments and good reliability in determining the presence of a leg-length inequality.

Use of subsequent anticoagulants to increase the predictive value of Medicaid deep venous thromboembolism diagnoses

Linked data bases that derive their information from health care administrative sources are increasingly being used to conduct pharmacoepidemiologic research. Computerized case ascertainment using these data would be highly advantageous in terms of time and cost considerations. For a study of oral-contraceptive-associated deep venous thromboembolism, we evaluated the utility of using anticoagulant treatment codes to validate diagnostic codes suggestive of deep venous thrombosis and pulmonary embolism. By requiring evidence of outpatient anticoagulant use within six months of hospitalization, the predictive value of case ascertainment increased from 42% to 65% for “probable” deep venous thromboembolism and from 70% to 97% for “possible” deep venous thromboembolism. In addition, use of anticoagulant treatment codes as a second marker of disease resulted in nondifferential outcome misclassification when the study base was restricted to current oral-contraceptive users. Use of confirmatory treatment claims may provide a rapid, cost-effective alternative to medical-record-based case ascertainment for pharmacoepidemiologic studies of selected outcomes conducted in Medicaid and other linked universal health care coverage populations.

A method of pharmacoepidemiologic analysis that uses computerized Medicaid

A method of pharmacoepidemiologic data analysis that utilizes computerized Medicaid data is presented. A cohort design in which Medicaid enrollees receiving drugs that are normally used to treat similar underlying conditions is described. A period of time in which Medicaid service transactions are evident is required before an individual is eligible for selection into a cohort. Selection of study subjects and descriptions of cohorts are based on Medicaid service histories occurring during the preliminary, prerequisite period. Time at risk is considered to begin after a prescription for a study drug is dispensed and continues until either a refill is dispensed, a prescription for an alternative drug within the same therapeutic class is dispensed, or a predetermined number of days has passed. Subjects are followed forward in time and relevant health care transactions that are suggestive of suspected adverse drug reactions are noted. Incidence densities associated with sequentially ranked prescriptions within sequential courses of therapy are compared. Methods to increase the accuracy of case ascertainment are briefly discussed. Separate validation studies may be used to evaluate the validity of computerized case ascertainment methods and to compensate for misclassification of outcome. The proposed method is intended to provide timely estimates of risk for selected outcomes. For outcomes that cannot be accurately ascertained from computerized data, this method may be useful in determining the feasibility of more customized studies.

Comments regarding "On prognosis" by William Farr (1838), with reconstruction of his longitudinal analysis of smallpox recovery and death rates

The editor has kindly asked me to comment from a statistical perspective on the historical article “On prognosis” by William Farr (1838). To place this article in context, I note that it was published about a year after the Registrar-General’s office was established in 1837, and a year before Farr’s appointment to his first official post as Compiler of Abstracts in this office, Farr later assumed the position of Superintendent of the Statistical Department in the RegistrarGeneral’s office, a position he held until his retirement in 1880 (Humphreys 1885). The article On prognosis is notable in many ways. It reveals Farr’s early insights into population-based epidemiologic principles, a fundamental understanding of longitudinal analysis, an interest in clinical research, and a commitment to explaining the course of health and disease in terms of “simple laws susceptible to calculation”. It is no wonder that Susser and Adelstein (1975) referred to Farr as “a founder, even the founder of epidemiology in its modern form”.

Steroidal contraceptive use update, United States, 1989-1994.

Objective — To update United States steroidal contraceptive use data for the period 1989 to 1994.

The reliability of muscle function analysis using different methods of stimulation

BACKGROUND The purpose of our study was to determine the reliability of nonvolitional muscle function analysis (MFA) by determining the day-to-day and within-day reliability of conventional electrical stimulation and a newer, magneto-electrical stimulation method, using standard laboratory methodology. METHODS Ten healthy, human immunodeficiency virus-negative adult men volunteered as subjects. MFA consisted of measuring the maximal relaxation rate, for magneto-electrical stimulation at 1 Hz and conventional electrical stimulation at 20 Hz, and force-frequency ratios using conventional electrical stimulation at 10 Hz:20 Hz and 10 Hz:50 Hz. Within-day and day-to-day reliability were determined by calculating the coefficient of variation (CV) for all subjects. RESULTS Maximal relaxation rate using magneto-electrical stimulation had a significantly lower CV compared with the other nonvolitional MFA methods (p = .002). CONCLUSIONS Maximal relaxation rate using magneto-electrical stimulation was more reliable and technically easier than the other muscle function parameters examined. However, the day-to-day CV of muscle function parameters is larger than traditional nutrition assessment techniques. Development within the field should strive to improve testing techniques so that the reliability of MFA will allow definition of a range of normal values against which an individuals value can be compared. Until this is available, the precision and reliability of MFA restrict its use to research and population studies.