Long-term eGFR decline in polycythemia vera compared with secondary polycythemia: a retrospective longitudinal cohort...

Polycythemia vera (PV) and secondary polycythemia are clinical conditions characterized by erythrocytosis, but their biological basis and clinical course differ. Whether this difference is reflected in long-term kidney function is not well defined. We aimed to compare longitudinal estimated glomerular filtration rate (eGFR) trajectories and kidney function loss in patients with PV and secondary polycythemia.

In this retrospective, single-center cohort, adult patients with PV or secondary polycythemia were evaluated from baseline through 4 years. Repeated eGFR measurements were examined using a linear mixed-effects model; the group-time interaction was the primary inferential test, with adjustment for age, sex, diabetes mellitus, hypertension, coronary artery disease, and baseline chronic kidney disease.

The cohort included 1,616 patients: 258 with PV and 1,358 with secondary polycythemia. The global group-time interaction indicated different eGFR trajectories (p = 0.049). The adjusted PV-secondary polycythemia eGFR contrast was small at baseline but indicated lower eGFR in PV by the fourth year (- 3.86 mL/min/1.73 m²; 95% CI, - 6.39 to - 1.33; Holm-corrected p = 0.014). The fourth-year contrast remained in the same direction in most sensitivity analyses.

PV was associated with a late and modest eGFR separation compared with secondary polycythemia. These findings support consideration of kidney function monitoring in selected patients with PV and prospective assessment of factors influencing renal progression.