Yuanchao Zheng

Antihypertensive Medication Use in Older Patients Transitioning from Chronic Kidney Disease to End-Stage Renal Disease on Dialysis

BACKGROUND AND OBJECTIVES The transition from CKD to ESRD can be particularly unstable, with high rates of death and hospitalizations. Few studies have examined medication use during this critical period. We examined patterns of antihypertensive medication use from the four quarters before and eight quarters after incident ESRD treated with maintenance dialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We used the US Renal Data System to identify patients aged ≥67 years initiating dialysis for ESRD between January 2008 and December 2010 with Medicare Part D and a low-income subsidy. We ascertained the incidence of AKI and hyperkalemia during each quarter on the basis of having at least 1 payment claim for the condition. We used Poisson regression with robust SEMs to formally test for changes in the trend and level of antihypertensive medication use in a series of intervention analyses. RESULTS The number of antihypertensive drugs used increased as patients neared ESRD, peaking at an average of 3.4 in the quarter immediately preceding dialysis initiation, then declining to 2.2 medications by 2 years later. Angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use was stable at approximately 40%, even among patients with coronary disease and systolic heart failure, and did not correlate with AKI or hyperkalemia. Dialysis initiation was associated with a 40% (95% confidence interval, 38% to 43%) lower adjusted level of diuretic use, which continued to decline after ESRD. Three- and four-drug combinations that included a diuretic were most common before ESRD, whereas after ESRD, one- and two-drug β-blocker or calcium-channel blocker-based combinations were most common. CONCLUSIONS The use of antihypertensive medications, particularly angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers and diuretics, may be suboptimal during the transition from CKD to ESRD, especially in patients with coronary disease or systolic heart failure. Future studies are needed to identify strategies to increase the appropriate use of antihypertensive medications during this critical transition period.

Prevalence of chronic kidney disease and risk factors for its progression: A cross-sectional comparison of Indians living in Indian versus U.S. cities

Background While data from the latter part of the twentieth century consistently showed that immigrants to high-income countries faced higher cardio-metabolic risk than their counterparts in low- and middle-income countries, urbanization and associated lifestyle changes may be changing these patterns, even for conditions considered to be advanced manifestations of cardio-metabolic disease (e.g., chronic kidney disease [CKD]). Methods and findings Using cross-sectional data from the Center for cArdiometabolic Risk Reduction in South Asia (CARRS, n = 5294) and Mediators of Atherosclerosis in South Asians Living in America (MASALA, n = 748) studies, we investigated whether prevalence of CKD is similar among Indians living in Indian and U.S. cities. We compared crude, age-, waist-to-height ratio-, and diabetes- adjusted CKD prevalence difference. Among participants identified to have CKD, we compared management of risk factors for its progression. Overall age-adjusted prevalence of CKD was similar in MASALA (14.0% [95% CI 11.8–16.3]) compared with CARRS (10.8% [95% CI 10.0–11.6]). Among men the prevalence difference was low (prevalence difference 1.8 [95% CI -1.6,5.3]) and remained low after adjustment for age, waist-to-height ratio, and diabetes status (-0.4 [-3.2,2.5]). Adjusted prevalence difference was higher among women (prevalence difference 8.9 [4.8,12.9]), but driven entirely by a higher prevalence of albuminuria among women in MASALA. Severity of CKD—-i.e., degree of albuminuria and proportion of participants with reduced glomerular filtration fraction-—was higher in CARRS for both men and women. Fewer participants with CKD in CARRS were effectively treated. 4% of CARRS versus 51% of MASALA participants with CKD had A1c < 7%; and 7% of CARRS versus 59% of MASALA participants blood pressure < 140/90 mmHg. Our analysis applies only to urban populations. Demographic—-particularly educational attainment—-differences among participants in the two studies are a potential source of bias. Conclusions Prevalence of CKD among Indians living in Indian and U.S. cities is similar. Persons with CKD living in Indian cities face higher likelihood of experiencing end-stage renal disease since they have more severe kidney disease and little evidence of risk factor management.

Do attributes of persons with chronic kidney disease differ in low-income and middle-income countries compared with high-income countries? Evidence from population-based data in six countries

Kidney biopsies to elucidate the cause of chronic kidney disease (CKD) are performed in a minority of persons with CKD living in high-income countries, since associated conditions—that is, diabetes mellitus, vascular disease or obesity with pre-diabetes, prehypertension or dyslipidaemia—can inform management targeted at slowing CKD progression in a majority. However, attributes of CKD may differ substantially among persons living in low-income and middle-income countries (LMICs). We used data from population or community-based studies from five LMICs (China, urban India, Moldova, Nepal and Nigeria) to determine what proportion of persons with CKD living in diverse regions fit one of the three major clinical profiles, with data from the US National Health Nutrition and Examination Survey as reference. In the USA, urban India and Moldova, 79.0%–83.9%; in China and Nepal, 62.4%–66.7% and in Nigeria, 51.6% persons with CKD fit one of three established risk profiles. Diabetes was most common in urban India and vascular disease in Moldova (50.7% and 33.2% of persons with CKD in urban India and Moldova, respectively). In Nigeria, 17.8% of persons with CKD without established risk factors had albuminuria ≥300 mg/g, the highest proportion in any country. While the majority of persons with CKD in LMICs fit into one of three established risk profiles, the proportion of persons who have CKD without established risk factors is higher than in the USA. These findings can inform tailored CKD detection and management systems and highlight the importance of studying potential causes and outcomes of CKD without established risk factors in LMICs.

Infrequent Provision of Palliative Care to Patients with Dialysis-Requiring AKI

BACKGROUND AND OBJECTIVES The use of palliative care in AKI is not well described. We sought to better understand palliative care practice patterns for hospitalized patients with AKI requiring dialysis in the United States. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Using the 2012 National Inpatient Sample, we identified patients with AKI and palliative care encounters using validated International Classification of Diseases, Ninth Revision, Clinical Modification codes. We compared palliative care encounters in patients with AKI requiring dialysis, patients with AKI not requiring dialysis, and patients without AKI. We described the provision of palliative care in patients with AKI requiring dialysis and compared the frequency of palliative care encounters for patients with AKI requiring dialysis with that for patients with other illnesses with similarly poor prognoses. We used logistic regression to determine factors associated with the provision of palliative care, adjusting for demographics, hospital-level variables, and patient comorbidities. RESULTS We identified 3,031,036 patients with AKI, of whom 91,850 (3%) received dialysis. We observed significant patient- and hospital-level differences in the provision of palliative care for patients with AKI requiring dialysis; adjusted odds were 26% (95% confidence interval, 12% to 38%) lower in blacks and 23% (95% confidence interval, 3% to 39%) lower in Hispanics relative to whites. Lower provision of palliative care was observed for rural and urban nonteaching hospitals relative to urban teaching hospitals, small and medium hospitals relative to large hospitals, and hospitals in the Northeast compared with the South. After adjusting for age and sex, there was low utilization of palliative care services for patients with AKI requiring dialysis (8%)-comparable with rates of utilization by patients with other illnesses with poor prognosis, including cardiogenic shock (9%), intracranial hemorrhage (10%), and acute respiratory distress syndrome (10%). CONCLUSIONS The provision of palliative care varied widely by patient and facility characteristics. Palliative care was infrequently used in hospitalized patients with AKI requiring dialysis, despite its poor prognosis and the regular application of life-sustaining therapy.

Associations of Glycemic Control With Cardiovascular Outcomes Among US Hemodialysis Patients With Diabetes Mellitus

Background There is a lack of data on the relationship between glycemic control and cardiovascular end points in hemodialysis patients with diabetes mellitus. Methods and Results We included adult Medicare‐insured patients with diabetes mellitus who initiated in‐center hemodialysis treatment from 2006 to 2008 and survived for >90 days. Quarterly mean time‐averaged glycated hemoglobin (HbA1c) values were categorized into <48 mmol/mol (<6.5%) (reference), 48 to <58 mmol/mol (6.5% to <7.5%), 58 to <69 mmol/mol (7.5% to <8.5%), and ≥69 mmol/mol (≥8.5%). Medicare claims were used to identify outcomes of cardiovascular mortality, nonfatal myocardial infarction (MI), fatal or nonfatal MI, stroke, and peripheral arterial disease. We used Cox models as a function of time‐varying exposure to estimate multivariable adjusted hazard ratios and 95%CI for the associations between HbA1c and time to study outcomes in a cohort of 16 387 eligible patients. Patients with HbA1c 58 to <69 mmol/mol (7.5% to <8.5%) and ≥69 mmol/mol (≥8.5%) had 16% (CI, 2%, 32%) and 18% (CI, 1%, 37%) higher rates of cardiovascular mortality (P‐trend=0.01) and 16% (CI, 1%, 33%) and 15% (CI, 1%, 32%) higher rates of nonfatal MI (P‐trend=0.05), respectively, compared with those in the reference group. Patients with HbA1c ≥69 mmol/mol (≥8.5%) had a 20% (CI, 2%, 41%) higher rate of fatal or nonfatal MI (P‐trend=0.02), compared with those in the reference group. HbA1c was not associated with stroke, peripheral arterial disease, or all‐cause mortality. Conclusions Higher HbA1c levels were significantly associated with higher rates of cardiovascular mortality and MI but not with stroke, peripheral arterial disease, or all‐cause mortality in this large cohort of hemodialysis patients with diabetes mellitus.

Trends in Rates of Lower Extremity Amputation Among Patients With End-stage Renal Disease Who Receive Dialysis

Importance Patients with end-stage renal disease (ESRD) who receive dialysis are at high risk of lower extremity amputation. Recent studies indicate decreasing rates of lower extremity amputation in non-ESRD populations, but contemporary data for patients with ESRD who receive dialysis are lacking. Objectives To assess rates of lower extremity amputation among patients with ESRD who receive dialysis during a recent 15-year period; to analyze whether those rates differed by age, sex, diabetes, or geographic region; and to determine 1-year mortality rates in this population after lower extremity amputation. Design, Setting, and Participants This retrospective study of 3 700 902 records obtained from a US national registry of patients with ESRD who receive dialysis assessed cross-sectional cohorts for each calendar year from 2000 through 2014. Adult patients with prevalent ESRD treated with hemodialysis or peritoneal dialysis covered by Medicare Part A and B on January 1 of each cohort year were included. Data analysis was conducted from August 2017 to April 2018. Exposures Age, sex, diabetes, and hospital referral region. Main Outcomes and Measures Annual rates per 100 person-years of nontraumatic major (above- or below-knee) and minor (below-ankle) amputations. Results For each annual cohort, there were fewer women (47.5% in 2000, 46.2% in 2005, 44.9% in 2010, and 44.0% in 2014) than men, more than half the patients were white individuals (58.1% in 2000, 56.9% in 2005, 56.9% in 2010, and 56.7% in 2014), and a small proportion were employed (13.9% in 2000, 15.1% in 2005, 16.1% in 2010, and 16.5% in 2014). The rate of lower extremity amputations for patients with ESRD who receive dialysis decreased by 51.0% from 2000 to 2014, driven primarily by a decrease in the rate of major amputations (5.42 [95% CI, 5.28-5.56] in 2000 vs 2.66 [95% CI, 2.59-2.72] per 100 person-years in 2014). Patients with diabetes had amputation rates more than 5 times as high as patients without diabetes. Patients younger than 65 years had higher adjusted amputation rates than older patients, and men had consistently higher adjusted amputation rates than women. Adjusted 1-year mortality rates after lower extremity amputation for patients with ESRD who receive dialysis decreased from 52.2% (95% CI, 50.9%-53.4%) in 2000 to 43.6% (95% CI, 42.5%-44.8%) in 2013. In general, amputation rates decreased among all regions from 2000 to 2014, but regional variability persisted across time despite adjustment for differences in patient demographics and comorbid conditions. Conclusions and Relevance Although rates of lower extremity amputations among US patients with ESRD who receive dialysis decreased by 51% during a recent 15-year period, mortality rates remained high, with nearly half of patients dying within a year after lower extremity amputation. Our results highlight the need for more research on ways to prevent lower extremity amputation in this extremely high-risk population.

Market Competition and Health Outcomes in Hemodialysis

OBJECTIVE To examine whether market competition is associated with improved health outcomes in hemodialysis. DATA SOURCES Secondary analysis of data from a national dialysis registry between 2001 and 2011. STUDY DESIGN We conducted one- and two-part linear regression models, using each hospital service area (HSA) as its own control, to examine the independent associations among market concentration and health outcomes. DATA COLLECTION We selected cohorts of patients receiving in-center hemodialysis in the United States at the start of each calendar year. We used information about dialysis facility ownership and the location where patients received dialysis to measure an index of market concentration-the Hirschman-Herfindahl Index (HHI)-for HSA and year, which ranges from near zero (perfect competition) to one (monopoly). PRINCIPAL FINDINGS An average reduction in HHI by 0.2 (one standard deviation in 2011) was associated with 2.9 fewer hospitalizations per 100 patient-years (95 percent CI, 0.4 to 5.4). If these findings were generalized to the entire in-center hemodialysis population, this would translate to 8,100 (95 percent CI 1,200 to 15,000) fewer hospitalizations in 2011. There was no association between change in market competition and mortality. CONCLUSIONS Market competition in dialysis may lead to improved health outcomes.