Health care utilization and receipt of cholesterol testing by veterans with and those without mental illness.

OBJECTIVE: We examined the relationship between mental illness, health care utilization and rates of cholesterol testing. METHODS: We conducted a retrospective cohort study using Veterans Affairs (VA) administrative data on 64,490 United States veterans who used VA New England Health Care System outpatient services between January 1998 and June 2001. A total of 10,100 veterans (15.7%) had a mental illness treated with medication. We examined the interaction between mental illness and outpatient service utilization with respect to the likelihood of receiving a cholesterol test, adjusting for major demographic and clinical covariates. RESULTS: Among veterans using VA outpatient services infrequently, those with mental illness were less likely than non-mentally ill control subjects to receive a cholesterol test during the study period (first quartile adjusted OR=0.45, 95% CI=0.37-0.54; second quartile adjusted OR=0.50, 95% CI=0.45-0.57). Mentally ill subjects with more frequent utilization of VA services were as likely as (third quartile adjusted OR=1.01, 95% CI=0.91-1.13) or more likely than (fourth quartile adjusted OR=2.73, 95% CI=2.46-3.03) non-mentally ill subjects to receive cholesterol testing. CONCLUSIONS: Mental illness was associated with a lower likelihood of cholesterol testing in subjects who used fewer VA outpatient services. The observed disparity attenuated at higher levels of service utilization.

Three complementary definitions of polypharmacy: methods, application and comparison of findings in a large prescription database.

PURPOSE: To develop and compare three operational definitions of polypharmacy using a large prescription database. METHODS: We defined Cumulative polypharmacy as all prescriptions filled during a 178 day window--which captured 95% of eventual refills as calculated from Kaplan-Meier and cumulative incidence curves. Continuous polypharmacy was all prescriptions filled in two such windows 6 months apart. Simultaneous polypharmacy was the number of prescriptions active on a particular day, as determined by fill dates and amount of medication given. We applied these definitions to the outpatient prescription files of New England veterans and compared the resulting estimates of polypharmacy using descriptive statistics. RESULTS: 118,013 patients received at least one prescription between January 1998 and July 1999. Cumulative polypharmacy averaged 3.54 (SD = 4.95) medications and continuous polypharmacy averaged 1.96 (SD = 3.23). Examination of simultaneous polypharmacy over 40 2-week intervals revealed an average of 2.63 (CI 2.61-2.65), a minimum of 1.09 (CI 1.08-1.10) and maximum of 4.94 (CI 4.92-4.96). One arbitrarily selected observation point had an average of 3.87 (SD = 3.17). CONCLUSIONS: Our definitions of cumulative and continuous polypharmacy serve to set upper and lower bounds for the estimate of polypharmacy. Our method for simultaneous polypharmacy gives numbers that diverge in some respects, but it is better at showing transient changes in medications. The methods are complementary and allow exploration of various aspects of medication use, such as cumulative medication exposure over time, the influence of chronic medical problems, and the causes of rapid changes in medications.