Comparing Healthcare Resource Utilization and Costs for Patients with Normal Tension Glaucoma Across Levels of Severity: A Retrospective Cohort Study

Abstract

Purpose

To estimate the healthcare resource utilization (HCRU) and costs for patients with normal tension glaucoma (NTG) as well as their payers across various levels of disease severity.

Patients and Methods

Our study was a retrospective cohort study of 6330 US NTG patients. Patients were enrolled if they were 40 years or older and had two or more qualifying NTG diagnoses within the enrollment period, October 1st, 2015 to December 31st, 2017. Our analysis was carried out for two cohorts – those with unilateral disease and those with bilateral disease. Baseline demographic and clinical characteristics were assessed for a 12-month pre-index period. The follow up period was 12-months post-index. We employed generalized linear models to model HCRU and costs.

Results

Patients with severe, bilateral disease, filled more than two additional prescriptions annually (2.5, p<0.001, 95% CI [2.0, 3.1]) when compared to their mild counterparts and accounted for 111 (p<0.001, 95% CI [83.5, 139.1]) extra days of supply of glaucoma medications. These patients face an adjusted $187 (p<0.001, 95% CI [145, 229]) more out-of-pocket (OOP), and payers an additional $598 (p<0.001, 95% CI [$370, $826]), than their counterparts with a mild diagnosis on an annual basis. Total annual payer costs, on average (SD) for those with severe bilateral NTG were $1175 ($2222).

Conclusion

Our results suggest that patient and payer burden is significantly greater for those with severe disease compared to those with mild NTG. The excess burden is attributed to additional HCRU and the associated financial burden. Payers experienced a much larger financial burden from patients with severe disease compared to those with mild NTG. Approximately half of the cost differences can be attributed to additional prescription use.

Keywords:

• healthcare resource utilization
• normal tension glaucoma
• low tension glaucoma
• healthcare costs

Abbreviations

CPI, consumer price index; HCRU, healthcare resource utilization; HIPAA, Health Insurance Portability and Accountability Act; ICD-10, international classification of diseases, tenth revision; IRB, institutional review board; NTG, normal-tension glaucoma; OAG, open-angle glaucoma; OOP, out-of-pocket; PPO, preferred provider organization; SD, standard deviation.

Acknowledgments

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

Beal was supported by a training grant from Legacy Allergan (AbbVie) at the time of this study and this work draws on work completed for his thesis project.¹³ Shih and Campbell were Legacy Allergan (AbbVie) employees at the time this study was conducted. The other authors have no conflicts of interest to disclose.