Combined pre-dialysis systolic blood pressure and pulse rate assessment for 1-year all-cause and cardiovascular mortality in patients on hemodialysis: a nationwide cohort study.

The prognostic utility of the combined assessment of pre-hemodialysis systolic blood pressure (SBP) and pulse rate compared to their independent assessment is unclear. In this nationwide cohort study, we aimed to determine whether their combined assessment could enhance the prognostic utility in patients on maintenance hemodialysis using the Japanese Renal Data Registry database. Exposure was defined as a combination of SBP and pulse rate. Forty-eight levels of exposure groups were created: SBP (<100, 100- < 120, 120- < 140, 140- < 160 [reference], 160- < 180, and ≥180 mmHg) and pulse rate (<50, 50- < 60, 60- < 70 [reference], 70- < 80, 80- < 90, 90- < 100, 100- < 110, and ≥110 beats/min). The primary and secondary outcomes were 1-year all-cause and cardiovascular mortalities, respectively. Multivariate Cox proportional hazards models were used, and multiplicative and additive interactions were assessed. The combined model for mortality and cardiac mortality was statistically better than the separate SBP and pulse rate model. Lower SBP was associated with higher risk of all-cause mortality irrespective of pulse rate. Most categories of lower SBP or higher pulse rate vs. the 120- < 140 mmHg and 70- < 80 beats/min category had positive relative excess risk due to interactions, with similar findings observed for cardiac mortality. Combined assessment of pre-dialysis SBP and pulse rate may help the simple stratification of patients with excess risks that cannot be identified by separate SBP and pulse rate assessment.