Care Gaps Following Newly Detected Dipstick Proteinuria in Treated Hypertension: A Japanese Nationwide Database Study.

AIMS: Clinical guidelines recommend follow-up quantitative testing after dipstick-positive proteinuria and, when proteinuria is confirmed, subsequent initiation of renin-angiotensin system inhibitors (RASi) in patients with hypertension. However, real-world adherence to these recommendations remains unclear. We investigated management patterns following newly detected dipstick proteinuria in patients with treated hypertension. METHODS: Using the JMDC claims database, we identified treated hypertensive patients with newly detected dipstick proteinuria (≥1+, with prior results <1+) between January 2005 and March 2025. The study outcomes were quantitative urine albumin/protein testing and RASi initiation. Cumulative incidence was estimated using the Kaplan-Meier method, and multivariable Cox models were used to identify factors associated with outcomes. RESULTS: The 365-day cumulative incidence of quantitative testing was 7.5% (95% CI: 7.2-7.7) in the overall population (n = 47,210), and that of RASi initiation was 13.2% (95% CI: 12.6-13.8) among baseline RASi non-users (n = 14,599). Both outcomes became more frequent with increasing dipstick grade but remained infrequent in the higher-grade groups: among patients with 2+ and 3+ proteinuria, quantitative testing was performed in 12.9% and 16.1%, respectively, and RASi initiation occurred in 17.5% and 21.7%, respectively. Temporal trend analysis indicated that RASi initiation rates showed no improvement (aHR per year: 1.01; 95% CI: 0.99-1.03). CONCLUSION: Follow-up quantitative testing and RASi initiation after newly detected dipstick proteinuria were infrequent, even among patients with higher dipstick grades, and RASi initiation showed no clear improvement over time. These findings highlight opportunities to improve guideline-concordant urinary protein assessment and antihypertensive therapy.