ASSOCIATION OF DIAGNOSIS CODE-BASED AND LABORATORY RESULTS-BASED KIDNEY FUNCTION WITH DEVELOPMENT OF VISION THREATENING DIABETIC RETINOPATHY

ABSTRACT

Purpose

To determine how kidney function identified by diagnosis codes compares to lab results-based kidney function for predicting the risk of vision-threatening diabetic retinopathy (VTDR).

Methods

A US medical claims database was used for this retrospective observational study. Adult patients enrolled from January 1, 2002 to December 31, 2016 with nonproliferative diabetic retinopathy (NPDR) were followed. Patients were excluded if they had any previous diagnosis or treatment of VTDR or VTDR diagnosed within 2 years of insurance plan entry. ICD9/10 Chronic kidney disease (CKD) diagnoses from outpatient claims were used to classify kidney disease with or without end-stage renal disease (ESRD). Serum creatinine was used to calculate estimated glomerular filtration rates (eGFR). Multivariate Cox models with time-dependent covariates were used to assess the associations of kidney disease diagnosis and eGFR with progression to VTDR, controlling for demographics and time-dependent covariates (systemic health, laboratory results, insulin use). C-statistic (a measure of model discrimination), hazard ratio (HR) and their 95% confidence intervals (CI) were calculated from multivariate Cox models.

Results

Among 69,982 patients with NPDR, 12,770 (18.2%) developed VTDR. C-statistic was identical (0.60, 95% CI: 0.59–0.60) for the multivariate model with eGFR and for the multivariate model with kidney diagnosis codes. eGFRs lower than 30 mL/min/1.73 m²(HR>1.14, p < .02 for all comparisons), and a diagnosis of ESRD (HR = 1.07, p = .02) were associated with higher risk of progression to VTDR.

Conclusions

Both diagnosis-based and lab results-based kidney function were associated with the development of VTDR and predict the development of VTDR equally well.

KEYWORDS:

• chronic kidney disease
• diabetic retinopathy
• pharmacoepidemiology
• claims data

Conflicts of interest

No conflicting relationship exists for any author.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

National Institutes of Health K23 Award (1K23EY025729 - 01) and University of Pennsylvania Core Grant for Vision Research (2P30EY001583). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. Additional funding was provided by Research to Prevent Blindness and the Paul and Evanina Mackall Foundation. Funding from each of the above sources was received in the form of block research grants to the Scheie Eye Institute. None of the organizations had any role in the design or conduction of the study.