Intradialytic Hypotension and Newly Recognized Peripheral Artery Disease in Patients Receiving Hemodialysis

Rationale & Objective Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients. Study Design Retrospective cohort study. Setting & Participants Linking data from the US Renal Data System to the electronic health records of a large dialysis provider, we identified adult patients (≥18 years of age) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD. Exposure The time-varying proportion of hemodialysis sessions with IDH defined as the nadir intradialytic systolic blood pressure <90 mm Hg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0% to <15%, 15% to <30%, and ≥30%. Outcomes Newly recognized PAD was ascertained using PAD diagnostic and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval. Analytical Approach To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted subdistribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure. Results Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association between IDH and newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (vs 0%) was associated with a 24% (95% CI, 17%-32%) higher hazard than having newly recognized PAD in the subsequent 30 days. Limitations Unmeasured confounding; ascertainment of PAD from claims. Conclusions Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD. Intradialytic hypotension (IDH) may decrease systemic circulation to the legs, exacerbating symptoms of peripheral artery disease (PAD). We sought to evaluate the relationship between IDH and newly recognized lower extremity PAD among hemodialysis patients. Retrospective cohort study. Linking data from the US Renal Data System to the electronic health records of a large dialysis provider, we identified adult patients (≥18 years of age) with Medicare Parts A and B who initiated dialysis (2006-2011) without previously recognized PAD. The time-varying proportion of hemodialysis sessions with IDH defined as the nadir intradialytic systolic blood pressure <90 mm Hg. We categorized the proportion of sessions with IDH within serial 30-day intervals as 0%, >0% to <15%, 15% to <30%, and ≥30%. Newly recognized PAD was ascertained using PAD diagnostic and procedure codes for amputation or revascularization, in serial 30-day intervals subsequent to each 30-day exposure interval. To account for the competing risks of death and kidney transplantation, we estimated unadjusted and adjusted subdistribution hazard ratios using the Kaplan-Meier multiple imputation method in combination with the extended Cox model to account for IDH as a time-varying exposure. Among 45,591 patients, those with more frequent baseline IDH had a higher prevalence of cardiovascular diseases. During 61,725 person-years of follow-up, 7,886 patients had newly recognized PAD. We found a graded, direct association between IDH and newly recognized PAD. For example, having IDH in ≥30% of dialysis sessions during a given 30-day interval (vs 0%) was associated with a 24% (95% CI, 17%-32%) higher hazard than having newly recognized PAD in the subsequent 30 days. Unmeasured confounding; ascertainment of PAD from claims. Patients receiving hemodialysis who had more frequent IDH had higher rates of newly recognized PAD. Patients with frequent IDH may warrant careful examination for PAD.