The combination assessment period, defined as the 30-day period following the index Rx date, was used to categorize patients into 2 cohorts: TIO alone or TIO + FSC (fluticasone propionate/salmeterol xinofoate combination) depending on whether they use FSC in combination with TIO during this period. Combination therapy with TIO + FSC was defined as having an FSC claim on the same date as the TIO claim or a TIO and FSC pharmacy claim with overlapping days supply occurring within 30 days of index Rx date. Enrollees adding FSC for the first time after the 30-day combination assessment period were excluded from the sample, thus ensuring that the TIO-alone cohort is not using FSC. No outcomes were assessed in the 30-day combination assessment period. The 1-year period after the end of the 30-day combination assessment period was termed as the follow-up period and was used to assess all study outcomes. Enrollees were required to be continuously eligible in their health plans during the pre-index and post-index periods for a total of 25 months. An intent-to-treat approach was used for the analyses. Thus, patients identified to be in a drug therapy cohort were considered to be using that therapy during the entire follow-up period, regardless of therapy discontinuations.