Interstitial cystitis : Cost, treatment and co-morbidities in an employed population

• Published in: PharmacoEconomics 2006, Vol.24 (1), p.55-65
• Main Authors: WU, Eric Q, BIRNBAUM, Howard, MAREVA, Milena, PARECE, Andrew, ZIHONG HUANG, MALLETT, David, TAITEL, Haya
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anti-Inflammatory Agents, Non-Steroidal - economics; Anti-Inflammatory Agents, Non-Steroidal - therapeutic use; Biological and medical sciences; Comorbidity; Cost-analysis; Cystitis, Interstitial - drug therapy; Cystitis, Interstitial - economics; Databases, Factual; Economics, Pharmaceutical; Employment; Female; Health Care Costs; Health technology assessment; Humans; Interstitial-cystitis; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Pentosan Sulfuric Polyester - economics; Pentosan Sulfuric Polyester - therapeutic use; Pentosan-polysulfate; Urinary system involvement in other diseases. Miscellaneous; Urinary tract. Prostate gland
• ISSN: 1170-7690; 1179-2027
• DOI: 10.2165/00019053-200624010-00005

Recent literature indicates that interstitial cystitis (IC) may affect 20% of women and a smaller proportion of men, although many individuals with IC may be misdiagnosed or remain undiagnosed. Factors that can contribute to the cost of IC include medical and drug utilisation related to treatment and diagnosis of IC and associated conditions (e.g. depression), as well as employee work loss. This study assesses the direct medical cost and indirect cost of work loss for IC patients in the first year after diagnosis, and evaluates IC treatment patterns and prevalence of co-morbidities. Data for patients under the age of 65 years with at least one diagnosis of IC (n = 749) were drawn from a de-identified, administrative database of approximately 2 million beneficiaries that included medical, drug and disability claims for 1999-2002. A 2 : 1 matched control sample of patients without an IC diagnosis (non-IC sample) was randomly selected based on patient characteristics. Indirect costs were calculated from a subgroup of 152 IC patients (plus their matched controls) who had disability information available. Costs incurred in the first year after IC diagnosis and co-morbidities were compared between IC patients and the non-IC sample, with the difference in costs defined as 'excess costs' of IC patients. Treatment patterns were profiled in the 2 months following initial diagnosis of IC. Descriptive statistics are presented. A multivariate two-part model was applied to estimate the IC direct medical cost, indirect cost and total cost to adjust for observed patient demographics and co-morbidities. Statistical significance was evaluated by the bootstrap method. The average IC patient had 130% higher direct costs (p < 0.05) and the average IC employee patient had 84% higher indirect costs than the average non-IC control individual. IC patients also had a higher diagnostic prevalence of prostatitis (relative risk [RR] = 40.0), endometriosis (RR = 7.4), vulvodynia (RR = 6.9), chronic pelvic pain (RR = 5.8) and urinary tract infections (RR = 5.1) [all p < 0.05]. IC patients were also more likely to report depression (RR = 2.8) and anxiety (RR = 4.5 ) than non-IC controls (all p < 0.05). Seventeen percent of IC patients received pentosan polysulfate therapy, the only US FDA-approved oral drug therapy indicated for treating IC, within the first 2 months after diagnosis. Of these patients, 69% received at least one 'other' drug from the non-approved oral medications studied.