Healthcare charges in patients who transition from ocular hypertension to primary open-angle glaucoma based on ophthalmic coding data

Introduction: The purpose of this research was to assess the impact of transition from ocular hypertension (OHT) to primary open-angle glaucoma (POAG) on healthcare charges. Methods: A case-control group was identified using PharMetrics claims database (1998-2005). Cases (n=1055) had a transition from OHT to POAG based on International Classification of Disease, Ninth Edition coding (ICD-9=365.11). Controls (n=2110) retained an ICD-9 code for OHT (ICD-9=365.04) and were matched to cases (2:1) on gender, age, diagnosis year, and follow-up time post-diagnosis. The index date marked the transition for cases and a date of similar duration after OHT diagnosis for controls. Conditional logistic regression and multiple linear regression models determined the impact of transitioning on healthcare charges. Results: Cases had significantly higher increases in ophthalmology-related charges ($797 vs. -$385, P<0.0001) but similar total healthcare charges ($1689 vs. $1386, P=0.8277) from the year pre- to year post-index date when compared with controls. After adjusting for key covariates, cases were 1.56 times (95% CI: 1.33-1.82) more likely to have increased total charges and 5.26 times (95% CI: 4.27-6.47) more likely to have increased ophthalmology-related charges compared with controls. In multiple linear regression analyses, cases experienced $48 (55%) higher increases in ophthalmology-related charges from the year pre- to year post-index date compared with controls ($85 vs. $37, respectively; P<0.0001). Conclusion: Patients with a transition from OHT to POAG based on ICD-9 coding had higher ophthalmology-related charges the year after transition compared with patients who retained a code for OHT. Prevention of this transition could result in healthcare resource savings.