Nephrology care prior to end-stage renal disease and outcomes among new ESRD patients in the USA

Abstract

Background: Longer nephrology care before end-stage renal disease (ESRD) has been linked with better outcomes.

Methods: We investigated whether longer pre-end-stage renal disease (ESRD) nephrology care was associated with lower mortality at both the patient and state levels among 443 761 incident ESRD patients identified in the USA between 2006 and 2010.

Results: Overall, 33% of new ESRD patients had received no prior nephrology care, while 28% had received care for >12 months. At the patient level, predictors of >12 months of nephrology care included having health insurance, white race, younger age, diabetes, hypertension and US region. Longer pre-ESRD nephrology care was associated with lower first-year mortality (adjusted hazard ratio = 0.58 for >12 months versus no care; 95% confidence interval 0.57-0.59), higher albumin and hemoglobin, choice of peritoneal dialysis and native fistula and discussion of transplantation options. Living in a state with a 10% higher proportion of patients receiving >12 months of pre-ESRD care was associated with a 9.3% lower relative mortality rate, standardized for case mix (R (2) = 0.47; P < 0.001).

Conclusions: This study represents the largest cohort of incident ESRD patients to date. Although we did not follow patients before ESRD onset, our findings, both at the individual patient and state levels, reflect the importance of early nephrology care among those with chronic kidney disease.

Keywords: dialysis; glomerular filtration rate; kidney transplantation; nephrology referral; vascular access.

Figures

Fig. 1.

Adjusted hazard ratios (and 95% confidence intervals) for mortality during the first year of dialysis, by duration of pre-ESRD nephrology care (12 months versus no care). Models were adjusted for age, gender, race, ethnicity, insurance, body mass index, diabetes as a cause of ESRD, comorbidities, year of incidence and nursing home residence. ESRD, end stage renal disease; Ref, reference category.

Fig. 2.

First-year state-specific standardized mortality ratio (SMR) by adjusted state-specific probability of >12 months of pre-ESRD nephrology care among US dialysis patients, 2007–10. The fitted regression line (Yˆ=1.22−0.93X; R2 = 0.47, P < 0.001) is given with pointwise 95% confidence intervals. Each state SMR is based on an adjusted comparison of first-year mortality in the dialysis populations of that state versus the USA, standardized to the US mean covariate values. Both the SMR and proportion with >12 months of pre-ESRD nephrology care were adjusted for the same covariates: patient's age, sex, race, ethnicity, body mass index, comorbidities at incidence, diabetes as the listed cause of ESRD, duration of ESRD, nursing home status and population death rates (SMR only). ESRD, end stage renal disease.

Fig. 3.

Adjusted1 OR (95% CI) for >12 months of pre-ESRD nephrology care versus no care by category of selected covariates. ASHD, atherosclerotic heart disease; BMI, body mass index; CI, confidence interval; CMS, Centers for Medicare and Medicaid Services; CVA, cerebrovascular atherosclerosis; COPD, chronic obstructive pulmonary disease; ESRD, end-stage renal disease; OR, odds ratio. 1Adjusted for age, sex, race, ethnicity, BMI, diabetes as a cause of ESRD, comorbidities (hypertension, cardiac failure, ASHD, CVA, COPD, cancer), insurance status, nursing home residence, year of incidence and CMS region. Regions are as follows—I: CT, MA, ME, NH, RI and VT; II: NJ, NY, VI and PR; III: DE, MD, PA, VA, WV and DC; IV: AL, FL, GA, KY, MS, NC, SC and TN; V: IL, IN, MI, MN, OH and WI; VI: AR, LA, NM, OK and TX; VII: IA, KS, MO and NE; VIII: CO, MT, ND, SD, UT and WY; IX: AZ, CA, HI, NV, AS, GU and MP; X: AK, ID, OR and WA. For state abbreviations, see http://www.stateabbreviations.us.