Thomas W. Croghan

Patient adherence and medical treatment outcomes: a meta-analysis.

Background. Adherence is a factor in the outcome of medical treatment, but the strength and moderators of the adherence-outcome association have not been systematically assessed. Objectives. A quantitative review using meta-analysis of three decades of empirical research correlating adherence with objective measures of treatment outcomes. Method. Sixty-three studies assessing patient adherence and outcomes of medical treatment were found involving medical regimens recommended by a nonpsychiatrist physician, and measuring patient adherence and health outcomes. Studies were analyzed according to disease (acute/chronic, severity), population (adult/child), type of regimen (preventive/treatment, use of medication), and type and sensitivity of adherence and outcomes measurements. Results. Overall, the outcome difference between high and low adherence is 26%. According to a stringent random effects model, adherence is most strongly related to outcomes in studies of nonmedication regimens, where measures of adherence are continuous, and where the disease is chronic (particularly hypertension, hypercholesterolemia, intestinal disease, and sleep apnea). A less stringent fixed effects model shows a trend for higher adherence-outcome correlations in studies of less serious conditions, of pediatric patients, and in those studies using self-reports of adherence, multiple measures of adherence, and less specific measures of outcomes. Intercorrelations among moderator variables in multiple regression show that the best predictor of the adherence-outcome relationship is methodological—the sensitivity/quality of the adherence assessment.

Determinants of Antidepressant Treatment Compliance: Implications for Policy:

Depression is among the most prevalent, devastating, and undertreated disorders in our society. Treatment with antidepressant medications is effective in controlling symptoms, but treatment beyond the point of symptom resolution is necessary to restore functional status and prevent recurrent episodes. An important step in improving compliance is to identify the determinants of antidepressant treatment compliance. A broader motivation for our study is to examine compliance by patients with a chronic but treatable disease. With claims data between 1990 and 1993, this study uses logistic regression analysis to examine the determinants of compliance among 2,012 antidepressant recipients. The results show that initiating treatment with a tricyclic antidepressant reduces the probability of antidepressant treatment compliance. Initiating treatment with a selective serotonin reuptake inhibitor and undergoing family, group, or individual psychotherapy treatments increase the probability of compliance. Case management does not meaningfully affect compliance. Implications for policy and clinical practice are discussed.

Use of claims data for research on treatment and outcomes of depression care.

BACKGROUND Data sources such as medical insurance claims are increasingly used in outcomes research. In this report, we present opportunities and limitations associated with the use of such data for outcomes research in the area of depression. OBJECTIVES The purpose of this report is to illustrate the use of administrative claims data in conducting research in the area of depression. Information in this report is intended to be helpful to both experienced health services researchers and to those who may be new to the field of either outcomes research or mental health research. FORMAT: This report covers measurement of outcomes, possible data sources, episode construction, and statistical methodologies that are appropriate when conducting depression research using claims data. Through examples and references, issues to be considered in each of these areas are examined and recommendations are made. Strengths and limitations of claims data will also be pointed out. CONCLUSIONS The use of claims data to conduct outcomes research in depression should be carried out responsibly. Limitations with using claims data to identify patients with depression must be acknowledged and appropriate methodologies should be used. Still, these data sources provide a rich opportunity to conduct outcomes research in depression, and much can be learned using administrative claims data.

A retrospective analysis of the revocation of prior authorization restrictions and the use of antidepressant medications for treating major depressive disorder

BACKGROUND The California Medicaid (Medi-Cal) program removed prior authorization restrictions for 2 selective serotonin reuptake inhibitors (SSRIs), fluoxetine and paroxetine, in May 1996. OBJECTIVE This article documents how open access affected patient compliance and the likelihood of switching antidepressant therapies. METHODS All Medi-Cal patients with a paid claim who had a diagnosis of major depressive disorder (MDD) from September 1994 through January 1999 were eligible. The impact of open access on patient compliance and drug switching was investigated using logistic regression models. Completed therapy was defined as 180 days of uninterrupted drug therapy at a minimum therapeutic dose. RESULTS A total of 6409 patient treatment episodes were identified, of which 80% involved the use of an antidepressant. The aggregate rate of drug therapy completion dropped from 23.2% before the change in formulary policy to 20.5% in the open-access period. There was no corresponding change in the likelihood of switching therapies. For fluoxetine-treated patients, the odds ratio for completing therapy relative to tricyclic antidepressant-treated patients dropped from 3.916 to 1.706 in the open-access period. Corresponding results for paroxetine-treated patients were 1.591 and 0.726, respectively. The reduction in the likelihood of completed therapy without a corresponding increase in switching is consistent with earlier results. Open access resulted in an influx of patients who were not previously treated with an antidepressant or reported by their physician as having an MDD. Physicians may have expanded the use of the open-access SSRIs to treat less severely ill patients. However, paid claims data do not provide sufficient information to accurately measure severity of illness. CONCLUSIONS It is unclear whether patients benefited clinically from the expansion of the Medi-Cal formulary. The significant changes in the characteristics of the patient population in response to open access (access effect) complicate attempts to measure the impact of open access on treatment patterns. Future analysis of the impact of open access on the cost of treating an episode of depression will also have to address this issue.

Effect of Antidepressant Choice on the Incidence and Economic Intensity of Hospitalization Among Depressed Individuals

This study identified differences in hospital utilization for mental health problems among depressed patients initially treated with selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs). A retrospective sample of 2,557 patients was obtained from a private insurance claims database. Quasi-experimental, two-stage multivariate regression modeling was used to estimate the likelihood of hospitalization and subsequent inpatient expenditures. Only 2% of the sample were hospitalized, and the average expenditures per admitted patient was about

Medicaid Beneficiaries Using Mental Health or Substance Abuse Services in Fee-for-Service Plans in 13 States, 2003

8,000. Patients initially prescribed sertraline had the same likelihood of hospitalization for a mental health problem as patients prescribed TCAs. Patients initially prescribed fluoxetine were half as likely to be hospitalized as patients initially prescribed TCAs. Once hospitalized, no differential effects of a specific antidepressant on inpatient expenditures were found.

The Effects of Adherence to Antidepressant Treatment Guidelines on Relapse and Recurrence of Depression

OBJECTIVE This study identified Medicaid beneficiaries using mental health or substance abuse services in fee-for-service plans in 13 states in 2003 (N=1,380,190) and examined their use of medical services. METHODS Administrative and fee-for-service claims data from Medicaid Analytic eXtract files were analyzed to identify mutually exclusive groups of beneficiaries who used either mental health or substance abuse services and to describe patterns of medical service use. RESULTS Overall, 11.7% of Medicaid beneficiaries were identified as using mental health or substance abuse services (10.9% and .7% used each of these services, respectively), with substantial variation across age and eligibility groups. Among beneficiaries using mental health services, 47.4% had visited an emergency room for any reason, 7.8% were treated for their disorder in inpatient settings, 13.8% received inpatient treatment for problems other than their mental or substance use disorders, and 70.4% received prescriptions for psychotropic medications. Among beneficiaries using substance abuse services, 60.7% had visited an emergency room, 12.6% were treated for their disorder in inpatient settings, 24.7% received other inpatient treatment, and 46.1% received prescriptions for psychotropic medications. Among beneficiaries not using either mental health or substance use services, 29.0% had visited an emergency room, 12.7% received inpatient treatment, and 10.1% received prescriptions for psychotropic medications. CONCLUSIONS Beneficiaries who used mental health or substance abuse services entered general inpatient settings and visited emergency rooms more frequently than other beneficiaries.