Health care resource utilization and expenditures in persons with autosomal dominant polycystic kidney disease

Neeraj N Iyer, Purdue University

Abstract

The objectives of this study were to determine prevalence of autosomal dominant polycystic kidney disease (ADPKD), to determine all-cause health care resource utilization and all-cause health care expenditures, to determine incremental health care resource utilization, and to determine incremental health care expenditures associated with ADPKD. An observational database analysis of a privately insured population was conducted using information from a large administrative claims database. Individuals 18 years of age or older and enrolled in a tracked health plan anytime during the period from April 1, 2011 through March 31, 2012, were eligible for inclusion in the sample for determination of ADPKD prevalence. To select the sample for estimating all-cause and incremental resource utilization and expenditures associated with ADPKD, administrative claims and enrollment records from April 1, 2011 through March 31, 2012 were examined to select individuals 18 years or older with ADPKD (n=3,844) based on ICD-9-CM diagnosis codes. ADPKD patients were linked one-to-one on age and gender with individuals without ADPKD resulting in 3,844 persons in the comparison group and a total of 7,688 persons in the overall sample. The number of individuals with ADPKD enrolled anytime during the period from April 1, 2011 through March 31, 2012, was identified and divided by the total population of covered individuals 18 years or older, during the same one year period to calculate prevalence of ADPKD. All-cause heath care resource utilization among individuals with ADPKD were estimated by counting the total number of hospitalizations, hospital days, nursing home confinements, nursing home days, outpatient visits and emergency room visits. All-cause heath care expenditures among individuals with ADPKD were estimated by summing standard price amounts from claims related to hospitals, nursing homes, outpatient services, emergency rooms, and prescription services. Incremental health care resource utilization and expenditures associated with ADPKD were estimated using regression models, adjusting for other risk factors including age, gender, comorbidities, cardiovascular disease, diabetes and geographical region. The prevalence of autosomal dominant PKD was one in 1,786 persons or 560 cases per million population. The 95 percent confidence interval for estimated prevalence was 1,742 to 1,833. Mean annual unadjusted resource utilization of hospital days 2.0 versus 0.45, and outpatient visits 21.1 versus 9.7 was substantially higher among persons with ADPKD as compared to persons without ADPKD. Mean annual unadjusted total expenditures $23,242 versus $6,230, mean hospital expenditures $6,646 versus $1,484, mean outpatient expenditures $12,625 versus $3,225, and mean medication expenditures $3,537 versus $1,380, were also higher among ADPKD patients as compared to individuals without ADPKD. Multivariate regression models adjusting for risk factors revealed incremental mean (standard error) resource use associated with ADPKD of 0.68 (0.090) hospital days, equal to 68 additional hospital days per 100 ADPKD patients, and 6.9 (0.28) outpatient visits, equal to 690 additional visits per 100 ADPKD patients. Mean (standard error) incremental total expenditures associated with PKD were $7,917 ($431). Mean incremental expenditures were largest for outpatient expenditures at $4,507 ($181), followed by mean incremental hospital expenditures of $2,385 ($241), and mean incremental medication expenditures of $1,456 ($71). Based on sub-group analysis by whether diagnosed with end-stage renal disease, mean incremental total expenditures were $3,053 ($374) among ADPKD patients without end-stage renal disease. In conclusion, ADPKD was associated with considerable incremental health care resource utilization and expenditures. Significant illness burden was found even before patients reached end-stage renal disease.

Degree

Ph.D.

Advisors

Thomas, Purdue University.

Subject Area

Pharmaceutical sciences|Public health

COinS