Metabolic Syndromes as Important Comorbidities in Patients of Inherited Retinal Degenerations: Experiences from the Nationwide Health Database and a Large Hospital-Based Cohort

Abstract

This study aimed to evaluate the medical and socioeconomic impacts of IRDs using the nationwide health database and a large hospital-based cohort. This retrospective cross-sectional cohort study used data from the nationwide National Health Insurance Research Database (NHIRD). All patients with IRD from January 2012 to December 2016 were selected from the NHIRD and matched with the general population at a ratio of 1:4. All variables, including comorbidities, medications, service utilization, and medical costs, within 1 year from the date of the IRD diagnosis, were analyzed. Disability data were retrieved from the Taiwan Inherited retinal degeneration Project (TIP), a medical center-based database. A total of 4447 and 17,788 subjects from the nationwide database were included in the IRD and control groups, respectively. The Charlson comorbidity index score was higher in the IRD group (0.74:0.52, p < 0.001). Yearly visits to the ophthalmology clinic were more frequent in the IRD group (6.80:1.06, p < 0.001), particularly to tertiary medical centers (p < 0.001). The IRD group showed greater odds ratios (OR) for metabolic syndrome-related comorbidities, including hypertension (OR = 1.18, 95% confidence interval (CI) 1.10 to 1.26) and diabetes (OR = 1.32, 95% CI 1.21 to 1.45), and double the average yearly medical cost (2104.3 vs. 1084.6 USD, p < 0.001) and ten times the yearly ophthalmology cost (369.1 vs. 36.1 USD, p < 0.001). The average disability level was 54.17% for all subjects. This study revealed the large medical and socioeconomic impacts of IRD on not only patients with IRD, but also their family members and the whole society.

Keywords: Charlson comorbidity index; inherited retinal degenerations; metabolic syndrome; socioeconomic impacts.

Figure 1

Patient flow diagram. Abbreviations: IRD, inherited retinal degeneration.

Figure 2

Differences between the patients with inherited retinal degenerations and the control group in the utilization of medical services and the relationship with the city urbanization level.

Figure 3

Odds ratio of comorbidities, medications, and managements. The odds ratios were calculated as the odds of IRD patients divided by the odds of control group. The odds were calculated as those with comorbidities in each group divided by those without comorbidities. (A) Odds ratios of the metabolic syndrome and other comorbidities were analyzed between the inherited retinal degeneration (IRD) and control groups. (B) Odds ratios of the common medications and procedures for metabolic syndrome were analyzed between the IRD and control groups. Abbreviations: AIDS, acquired immune deficiency syndrome; DM, diabetes mellitus; HTN, hypertension; PAD, peripheral artery disease; PCI, percutaneous coronary interventions; CABG, coronary bypass graft surgery; PTA, percutaneous transluminal angiography.

Figure 4

Mean yearly medical costs of patients with inherited retinal degenerations and the general population. Abbreviations: IRD, inherited retinal degeneration.

Figure 5

Rate differences in the specialty usage between patients with internal retinal degenerations and the general population. All aforementioned items significantly differed between the groups, with p < 0.001. However, we considered the significance to be “clinically meaningful” at a difference of at least 0.3%.

Figure 6

Disability-level distribution and disability percentage of patients with inherited retinal degenerations.

Figure 7

A brief summary of medical and socioeconomic impacts of inherited retinal degenerations. Abbreviations: IRD, inherited retinal degeneration.