A Matched-Cohort Study of Selected Clinical and Utilization Outcomes for an Asthma Care Support Program

Abstract

Estimating the economic and clinical impact of asthma disease management programs traditionally has relied on non-experimental designs and employed matching or stratification methods with limited success. Selecting similar comparison subjects is problematic since subjects must be compared across numerous pretreatment factors. In cases where treatment and comparison subjects differ greatly on observed characteristics, conclusions may be particularly sensitive to an incorrectly specified model used for matching. A propensity score method constructs matched samples of treated-control pairs, addresses program selection bias, and reduces bias in estimates of treatment effects. To investigate the program effects of an asthma care support program delivered to high-risk asthmatics (persons with a previous inpatient admission, emergency department [ED] visit, or observation visit), we conducted a matched-cohort study on 196 participants. Using administrative claims data and selected clinical indicators, we analyzed hospitalization, ED, and physician office visit rates to estimate effects of program enrollment. Total hospitalizations, asthma-related hospitalizations, bed days, and ED visits for participants were lower and statistically different from that of the matched-cohort group during the program period, suggesting the beneficial effects of monitoring, education, and counseling activities for participants. Where controlled randomized clinical trials cannot be performed because of ethical, cost, or feasibility issues, the use of propensity scores provides an alternative for estimating treatment effects using observational data. This study employs a propensity score-matching methodology to select a subset of comparison units most comparable to treatment units, and documents the beneficial outcomes of participation in an asthma care support program.

Disease Management Programs for Patients With Asthma in Germany: A Longitudinal Population-Based Study

“…These data confirm results from Suh et al, 27 who identified a similar reduction from more than 40% of patients with OCS after a comparable intervention. Likewise, Johnson et al 31 conducted a matched cohort investigation to find that participants in a DMP had a significantly lower usage of OCS than non-participants. On the other hand, Windt and Glaeske 6 observed no significant difference between DMP participants and non-participants.…”

Adult Asthma Disease Management: An Analysis of Studies, Approaches, Outcomes, and Methods

“…Two of the 29 studies presented results from the same intervention, 10,11 and 2 others presented results from another intervention. 12,13 Of the 27 included studies: 5 were RCTs, 14-18 7 were before/after observational studies with a control group; 12,13,[19][20][21][22][23][24] 12 were before/after observational studies without a control group; 10,11,[25][26][27][28][29][30][31][32][33][34][35] and 3 were after-only observational studies with a control group [36][37][38] (see Fig. 1 and Table 1).…”

“…20,24,31 Eleven studies enrolled higher-risk (moderate-to-severe asthma) patients. [12][13][14][15]17,19,26,27,30,32,33,36 Five studies enrolled a broad spectrum of patients. 10,11,18,22,35,37 Eight studies did not report patient risk.…”

Estimation of Treatment Effect of Asthma Case Management Using Propensity Score Methods

“…We randomly assigned each potential control a "start date" based on the actual distribution of program start dates of participants (see Johnson et al, 2005) to create comparable pre-treatment and post-treatment periods. Because asthma symptoms often show seasonal patterns (Gergen et al, 2002), we consider outcomes at six-months and twelve-months after the intervention.…”