J. Alexander Cole

Severe vascular events in migraine patients

Objective.—To estimate rates of vascular events in relation to dispensing of triptans and ergot alkaloids among migraineurs, and to compare these rates with those of nonmigraineurs.

Migraine, fibromyalgia, and depression among people with IBS: a prevalence study

BackgroundCase descriptions suggest IBS patients are more likely to have other disorders, including migraine, fibromyalgia, and depression. We sought to examine the prevalence of these conditions in cohorts of people with and without IBS.MethodsThe source of data was a large U.S. health plan from January 1, 1996 though June 30, 2002. We identified all people with a medical claim associated with an ICD-9 code for IBS. A non-IBS cohort was a random sample of people with an ICD-9 code for routine medical care. In the cohorts, we identified all claims for migraine, depression, and fibromyalgia. We estimated the prevalence odds ratios (PORs) of each of the three conditions using the Mantel-Haenszel method. We conducted quantitative sensitivity analyses to quantify the impact of residual confounding and in differential outcome identification.ResultsWe identified 97,593 people in the IBS cohort, and a random sample of 27,402 people to compose the non-IBS comparison cohort. With adjustment, there was a 60% higher odds in the IBS cohort of having any one of the three disorders relative to the comparison cohort (POR 1.6, 95% CI 1.5 – 1.7). There was a 40% higher odds of depression in the IBS cohort (POR 1.4, 95% CI 1.3 – 1.4). The PORs for fibromyalgia and migraine were similar (POR for fibromyalgia 1.8, 95% CI 1.7 – 1.9; POR for migraine 1.6, 95% CI 1.4 – 1.7). Differential prevalence of an unmeasured confounder, or imperfect sensitivity or specificity of outcome detection would have impacted the observed results.ConclusionPeople in the IBS cohort had a 40% to 80% higher prevalence odds of migraine, fibromyalgia, and depression.

Drug Copayment and Adherence in Chronic Heart Failure: Effect on Cost and Outcomes

Study Objective. To measure the association among prescription copayment, drug adherence, and subsequent health outcomes among patients with chronic heart failure (CHF).

Occurrence of colon ischemia in relation to irritable bowel syndrome

OBJECTIVE:In November 2000, alosetron HCl (Lotronex®), a treatment for irritable bowel syndrome (IBS), was removed from the U.S. market in part because of the occurrence of colon ischemia in treated patients. Since the relation between colon ischemia and IBS is poorly understood, we evaluated the incidence of colon ischemia among people with and without IBS.METHODS:Using medical claims data from a large health care organization in the United States, we identified 87,449 people with an IBS diagnosis between January 1995 and December 1999. We calculated age- and sex-specific incidence rates in the general population and in IBS patients.RESULTS:There were 740 cases of colon ischemia during 8.5 million person-years of observation in 5.4 million persons. The crude incidence rate was 42.8 cases per 100,000 person-years for IBS patients. By comparison, the incidence rate was 7.2 per 100,000 person-years in the general population. After adjustment for age, sex, and calendar year, the incidence of colon ischemia in people with IBS was 3.4 times higher than in persons without (95% CI 2.6–4.5).CONCLUSIONS:Rates of colon ischemia among patients carrying a diagnosis of IBS are substantially higher than in the general population. Colon ischemia, though unusual in IBS patients, may nonetheless constitute a distinct part of the IBS natural history. Alternatively, it may be a consequence of therapy, or a manifestation of other bowel pathology that is sometimes confused with IBS.

The incidence of abdominal and pelvic surgery among patients with irritable bowel syndrome

Rates of abdominopelvic surgery, with a particular focus on gallbladder procedures, were measured in patients with irritable bowel syndrome (IBS) (n= 108,936) and compared with those in a general population sample (n= 223,082). The patient sample was selected from persons who were members of a managed care organization during the years 1995–2000. Medical records from a randomly selected subset of IBS patients were reviewed to confirm the diagnosis. Crude and standardized rates and adjusted rate ratios for surgery were calculated. The incidence of abdominopelvic surgery, excluding gallbladder procedures, was 87% higher in patients with IBS than that for the general population. The incidence of gallbladder surgery was threefold higher in IBS patients than the general population. Patients with IBS have an increased risk for abdominopelvic and gallbladder surgery and, thus, an associated risk for experiencing morbidity and mortality associated with these surgical procedures.

The effect of zanamivir treatment on influenza complications: A retrospective cohort study

BACKGROUND Complications of influenza are a major cause of morbidity and mortality during the influenza season. Clinical trials of zanamivir have reported a reduced incidence of influenza complications among high-risk patients. OBJECTIVES This retrospective study sought to determine whether the use of zanamivir lowers the risk of acute influenza complications in a broader population, based on an analysis of claims data from a large managed care organization. METHODS Medical and pharmacy health insurance claims data from October 1, 1999, through April 30, 2000, were compiled for UnitedHealthcare members in 19 states. All patients with a diagnosis of influenza (International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic code 487.xx) associated with a physician visit were identified. From these, all patients were selected who had received zanamivir on the same day as the diagnosis of influenza. The propensity score matching technique was used to identify a comparison group with similar health service utilization and comorbidities who received a diagnosis of influenza but no antiviral therapy. Follow-up started the day after the influenza diagnosis and continued for 21 days. RESULTS From the 43,741 patients originally identified, 2341 were selected who received a simultaneous diagnosis of influenza and a prescription for zanamivir. The untreated comparator group numbered 2337. Fewer zanamivir patients than untreated patients were hospitalized for complications, and the absolute risks were low (0.6% and 1.0%, respectively; risk ratio [RR], 0.58; 95% CI, 0.30-1.12). Zanamivir-treated patients had an excess of outpatient visits (16.9% vs 14.5%; RR, 1.16; 95% CI, 1.02-1.33) and antibiotic use (16.3% vs 14.8%; RR, 1.10; 95% CI, 0.97-1.26), although the RRs were modest. CONCLUSIONS In the setting of a large managed care plan, patterns of influenza complications were similar in zanamivir-treated and untreated patients with a diagnosis of influenza. The results of this study are in contrast to those of published clinical trials reporting a reduction in the risk of influenza complications in zanamivir-treated patients.

Incidence of IBS in a cohort of people with asthma

We conducted a study to examine the relation of asthma and its treatment to irritable bowel syndrome (IBS). We identified cohorts of members with and without asthma from January 1996 though June 2002 and calculated rates of IBS in both cohorts. In a nested case-control study, we calculated odds ratios for oral steroid dispensings before IBS onset. To address differential IBS detection, we conducted a quantitative sensitivity analysis. We identified 91,237 people with asthma and sample of 24,518 people without asthma. There was a 20% increase in the incidence of IBS among people with asthma (standardized morbidity ratio = 1.2; 95% CI, 1.0–1.5), and no association between oral steroids and IBS among people with asthma (OR = 1.0; 95% CI, 0.9–1.1.) Misclassification of IBS would have biased the rate ratio toward the null. We observed a small increase in IBS among people with asthma, and no association between oral steroids and IBS onset among asthma patients.

Risk for respiratory events in a cohort of patients receiving inhaled zanamivir: A retrospective study

BACKGROUND Inhaled zanamivir is indicated for treatment of uncomplicated acute illness due to influenza A and B viruses in patients aged > or = 12 years who have been symptomatic for no more than 2 days. OBJECTIVE The primary objective of this study was to estimate the incidence of adverse respiratory events among zanamivir-treated patients under conditions of usual care. METHODS The Ingenix research database includes insurance claims for all dispensations, inpatient and outpatient services, and procedures including the associated diagnoses and costs for a subset of all enrolled UnitedHealthcare members. We identified all persons with a dispensation of zanamivir recorded between October 1, 1999, and April 30, 2000. We captured medical and pharmaceutical claims data for the 6 months before the dispensation to obtain information about comorbidities, overall health status, and respiratory events. Medical and hospital record abstraction and clinical review served to confirm inpatient/emergency department (ED) events. We also examined the records of an approximately 10% random sample of patients treated for a potential respiratory event in an outpatient/ physician office visit during the 10-day follow-up period. Respiratory events not sufficiently severe to result in medical care were not captured in this study. RESULTS A total of 5498 eligible zanamivir dispensations contributed by 5450 patients (2911 females, 2539 males; mean age, 38.8 years), with 40 confirmed inpatient/ED respiratory events, were included in the study. Of these 40 events, 31 were pneumonia, bronchitis, or exacerbations of existing chronic respiratory disease; none required intubation or ventilation. No events occurred on the dispensation date. The overall risk for an inpatient/ ED respiratory event was 0.7 per 100 episodes (95% CI, 0.5-1.0). Seven events of wheezing or shortness of breath were not an obvious extension of the original influenza-like illness or of a complicating bronchitis (risk = 0.13 per 100 episodes; 95% CI, 0.06-0.26). CONCLUSIONS No immediate or severe bronchoconstrictive responses occurred among 5498 zanamivir dispensations. The overall risk for any respiratory event was low, and none was sufficiently severe to suggest respiratory failure.