A Novel Approach to Developing a Discordance Index for Older Adults with Chronic Kidney Disease

BACKGROUND:

Older adults with chronic kidney disease (CKD)-discordant conditions (comorbid conditions with treatment recommendations that potentially complicate CKD management) have greater risk of hospitalization and death. Our goal was to develop a CKD-Discordance Index using electronic health records to improve recognition of discordance.

METHODS:

This retrospective cohort included Kaiser Permanente Southern California patients aged ≥65 years with incident CKD (N=30,932). To guide inclusion of conditions in the Index and weight each condition, we first developed a prediction model for 1-year hospitalization risk using Cox regression. Points were assigned proportional to regression coefficients derived from the model. Next, the CKD-Discordance Index was calculated as an individual’s total points divided by the maximum possible discordance points. The association between CKD-Discordance Index and hospitalizations, ED visits, and mortality was accessed using multivariable adjusted Cox regression.

RESULTS:

Overall, mean (SD) age was 77.9 (7.6), 55% were female, 59.3% were white, and 32% (n=9,869) had ≥1 hospitalization during 1 year of follow-up. The CKD-Discordance Index included the following: heart failure, gastroesophageal reflux disease/peptic ulcer disease, osteoarthritis, dementia, depression, cancer, chronic obstructive pulmonary disease/asthma, and having ≥4 prescribers. Compared to those with a CKD-Discordance Index of 0, adjusted hazard ratios (95% CI) for hospitalization were 1.39 (1.27-1.51) and 1.81 (1.64-2.01) for those with a CKD-Discordance Index of 0.001-0.24 and ≥0.25, respectively (Ptrend<0.001). A graded pattern of risk was seen for ED visits and all-cause mortality.

CONCLUSION:

A data-driven approach identified CKD-discordant indicators for a CKD-Discordance Index. Higher CKD-Discordance Index was associated with healthcare utilization and mortality.