Characterizing the severe asthma population in the United States: claims-based analysis of three treatment cohorts in the year prior to treatment escalation.

OBJECTIVES

Little is known about the disposition of severe patients prior to treatment escalation. To classify patients by treatment step using pharmacy data and describe their economic and healthcare utilization, insurance status, and sociodemographic characteristics in the year prior to escalation to Global Initiative for Asthma (GINA) steps 4 and 5.

METHODS

This was a retrospective claims cohort study of asthma patients (age 12-75 years) newly initiated on "stable therapy" (three consecutive months of therapy) with omalizumab, high intensity corticosteroids (HICS; ≥1000 µg/d inhaled fluticasone equivalent or oral prednisone), or high-dose inhaled corticosteroid (HDICS; ≥500-<1000 µg/d fluticasone equivalent) from 2002 to 2011. Other asthma treatments were compared as a reference.

RESULTS

Of 25,297 patients, 856 initiated omalizumab, 6926 initiated HICS, and 11,445 initiated HDICS. In the year prior to treatment escalation to omalizumab, HICS, and HDICS, respectively, individuals had high annual mean medical expenditures ($14,071, $12,030, and $7570), utilization (27 outpatient and 10 specialty care visits; 19 outpatient and three specialty; 15 outpatient and two specialty), asthma-related prescription drugs (11.74, 7.8, and 5.17) and chronic comorbidities (2.68, 2.67, and 2.19). Prior to omalizumab treatment, patients were more likely to be salaried, full-time employees with commercial PPO/POS insurance.

CONCLUSIONS

Prior to escalating treatment to GINA steps 4 and 5, individuals experienced significant annual medical expenditures, healthcare resource utilization and polypharmacy burden, which may reflect poorly controlled asthma and the need to escalate treatment. Medical claims data and utilization-based measures may be helpful in classifying individuals by GINA treatment step.