Center practice drives variation in choice of US kidney transplant induction therapy: a retrospective analysis of contemporary practice

To assess factors that influence the choice of induction regimen in contemporary kidney transplantation, we examined center-identified, national transplant registry data for 166 776 US recipients (2005-2014). Bilevel hierarchical models were constructed, wherein use of each regimen was compared pairwise with use of interleukin-2 receptor blocking antibodies (IL2rAb). Overall, 82% of patients received induction, including thymoglobulin (TMG, 46%), IL2rAb (22%), alemtuzumab (ALEM, 13%), and other agents (1%). However, proportions of patients receiving induction varied widely across centers (0-100%). Recipients of living donor transplants and self-pay patients were less likely to receive induction treatment. Clinical factors associated with use of TMG or ALEM (vs. IL2rAb) included age, black race, sensitization, retransplant status, nonstandard deceased donor, and delayed graft function. However, these characteristics explained only 10-33% of observed variation. Based on intraclass correlation analysis, "center effect" explained most of the variation in TMG (58%), ALEM (66%), other (51%), and no induction (58%) use. Median odds ratios generated from case-factor adjusted models (7.66-11.19) also supported large differences in the likelihood of induction choices between centers. The wide variation in induction therapy choice across US transplant centers is not dominantly explained by differences in patient or donor characteristics; rather, it reflects center choice and practice.

Influence of kidney offer acceptance behavior on metrics of allocation efficiency

We investigated associations of deceased donor kidney offer acceptance with likelihood of the kidney being discarded, cold ischemia time at transplant (CIT), and likelihood of the kidney being exported outside the donation service area (DSA). We used kidney offers from donors in the Scientific Registry of Transplant Recipients July 1, 2015-June 30, 2016, and a stratified logistic regression to estimate odds ratios of acceptance for candidates wait-listed in a DSA. We estimated associations between these ratios and likelihood of discard or export and CIT at transplant. Approximately 0.50 kidneys were discarded per donor; lower DSA-specific offer acceptance ratios were associated with more discards (R=-0.20; P=0.006). For a median donor, the DSA with the highest acceptance ratio would place 0.12 more kidneys per donor than the DSA with the lowest ratio. Low acceptance ratios were associated with higher CIT (R=-0.23; P<0.001). For the median donor, CIT was 2.9 hours shorter for the DSA with the highest versus lowest acceptance ratio. Low acceptance ratios were associated with more exports (R=-0.43; P<0.001); the probability was 15% higher for a median donor in the DSA with the lowest versus highest acceptance ratio. Improving lower-than-expected offer acceptance would likely reduce discards, CIT, and exports.

Summary of Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors

Kidney Disease: Improving Global Outcomes (KDIGO) engaged an evidence review team and convened a work group to produce a guideline to evaluate and manage candidates for living kidney donation. The evidence for most guideline recommendations is sparse and many "ungraded" expert consensus recommendations were made to guide the donor candidate evaluation and care before, during, and after donation. The guideline advocates for replacing decisions based on assessments of single risk factors in isolation with a comprehensive approach to risk assessment using the best available evidence. The approach to simultaneous consideration of each candidate's profile of demographic and health characteristics advances a new framework for assessing donor candidate risk and for defensible shared decision making.

KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors

The 2017 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors is intended to assist medical professionals who evaluate living kidney donor candidates and provide care before, during and after donation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach and guideline recommendations are based on systematic reviews of relevant studies that included critical appraisal of the quality of the evidence and the strength of recommendations. However, many recommendations, for which there was no evidence or no systematic search for evidence was undertaken by the Evidence Review Team, were issued as ungraded expert opinion recommendations. The guideline work group concluded that a comprehensive approach to risk assessment should replace decisions based on assessments of single risk factors in isolation. Original data analyses were undertaken to produce a "proof-in-concept" risk-prediction model for kidney failure to support a framework for quantitative risk assessment in the donor candidate evaluation and defensible shared decision making. This framework is grounded in the simultaneous consideration of each candidate's profile of demographic and health characteristics. The processes and framework for the donor candidate evaluation are presented, along with recommendations for optimal care before, during, and after donation. Limitations of the evidence are discussed, especially regarding the lack of definitive prospective studies and clinical outcome trials. Suggestions for future research, including the need for continued refinement of long-term risk prediction and novel approaches to estimating donation-attributable risks, are also provided.In citing this document, the following format should be used: Kidney Disease: Improving Global Outcomes (KDIGO) Living Kidney Donor Work Group. KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors. Transplantation. 2017;101(Suppl 8S):S1-S109.

A Five-Tier System for Improving the Categorization of Transplant Program Performance

OBJECTIVE

To better inform health care consumers by better identifying differences in transplant program performance.

DATA SOURCE

Adult kidney transplants performed in the United States, January 1, 2012-June 30, 2014.

STUDY DESIGN

In December 2016, the Scientific Registry of Transplant Recipients instituted a five-tier system for reporting transplant program performance. We compare the differentiation of program performance and the simulated misclassification rate of the five-tier system with the previous three-tier system based on the 95 percent credible interval.

DATA COLLECTION

Scientific Registry of Transplant Recipients database.

PRINCIPAL FINDINGS

The five-tier system improved differentiation and maintained a low misclassification rate of less than 22 percent for programs differing by two tiers.

CONCLUSION

The five-tier system will better inform health care consumers of transplant program performance.

Predonation Prescription Opioid Use: A Novel Risk Factor for Readmission After Living Kidney Donation

Implications of opioid use in living kidney donors for key outcomes, including readmission rates after nephrectomy, are unknown. We integrated Scientific Registry of Transplant Recipients data with records from a nationwide pharmacy claims warehouse and administrative records from an academic hospital consortium to quantify predonation prescription opioid use and postdonation readmission events. Associations of predonation opioid use (adjusted odds ratio [aOR]) in the year before donation and other baseline clinical, procedural, and center factors with readmission within 90 days postdonation were examined by using multivariate logistic regression. Among 14 959 living donors, 11.3% filled one or more opioid prescriptions in the year before donation. Donors with the highest level of predonation opioid use (>305 mg/year) were more than twice as likely as nonusers to be readmitted (6.8% vs. 2.6%; aOR 2.49, 95% confidence interval 1.74-3.58). Adjusted readmission risk was also significantly (p < 0.05) higher for women (aOR = 1.25), African Americans (aOR = 1.45), spouses (aOR = 1.42), exchange participants (aOR = 1.46), uninsured donors (aOR = 1.40), donors with predonation estimated glomerular filtration rate <60 mL/min/1.73 m² (aOR = 2.68), donors with predonation pulmonary conditions (aOR = 1.54), and after robotic nephrectomy (aOR = 1.68). Predonation opioid use is independently associated with readmission after donor nephrectomy. Future research should examine underlying mechanisms and approaches to reducing risks of postdonation complications.

Survival implications of opioid use before and after liver transplantation

Implications of prescription opioid use for outcomes after liver transplantation (LT) have not been described. We integrated national transplant registry data with records from a large pharmaceutical claims clearinghouse (2008-2014; n = 29,673). Opioid fills on the waiting list were normalized to morphine equivalents (MEs), and exposure was categorized as follows: > 0-2 ME/day (level 1), > 2-10 ME/day (level 2), > 10-70 ME/day (level 3), and >70 ME/day (level 4). Associations (adjusted hazard ratio [aHR], _{95% LCL} aHR _{95% UCL} ) of pretransplant ME level with patient and graft survival over 5 years after transplant were quantified by multivariate Cox regression including adjustment for recipient, donor, and transplant factors, as well as propensity adjustment for opioid use. Overall, 9.3% of recipients filled opioids on the waiting list. Compared with no use, level 3 (aHR _1.06 1.28_1.55 ) and 4 (aHR _1.16 1.52_1.98 ) opioid use during listing were associated with increased mortality over 5 years after transplant. These associations were driven by risk after the first transplant anniversary, such that mortality >1-5 years increased in a graded manner with higher use on the waiting list (level 2, aHR, _1.00 1.27_1.62 ; level 3, aHR, _1.08 1.38_1.77 ; level 4, aHR, _1.49 2.01_2.72 ). Similar patterns occurred for graft failure. Of recipients with the highest level of opioids on the waiting list, 65% had level 3 or 4 use in the first year after transplant, including 55% with use at these levels from day 90-365 after transplant. Opioid use in the first year after transplant also bore graded associations with subsequent death and graft loss >1-5 years after transplant. Opioid use history may be relevant in assessing and providing care to LT candidates. Liver Transplantation 23 305-314 2017 AASLD.

Recommendations for kidney disease guideline updating: a report by the KDIGO Methods Committee

Updating rather than de novo guideline development now accounts for the majority of guideline activities for many guideline development organizations, including Kidney Disease: Improving Global Outcomes (KDIGO), an international kidney disease guideline development entity that has produced guidelines on kidney diseases since 2008. Increasingly, guideline developers are moving away from updating at fixed intervals in favor of more flexible approaches that use periodic expert assessment of guideline currency (with or without an updated systematic review) to determine the need for updating. Determining the need for guideline updating in an efficient, transparent, and timely manner is challenging, and updating of systematic reviews and guidelines is labor intensive. Ideally, guidelines should be updated dynamically when new evidence indicates a need for a substantive change in the guideline based on a priori criteria. This dynamic updating (sometimes referred to as a living guideline model) can be facilitated with the use of integrated electronic platforms that allow updating of specific recommendations. This report summarizes consensus-based recommendations from a panel of guideline methodology professionals on how to keep KDIGO guidelines up to date.

OPTN/SRTR 2015 Annual Data Report: Economics

While the costs to Medicare of solid organ transplants are varied and considerable, the total Medicare expenditure of $4.4 billion for solid organ transplant recipients in 2014 remained less than 1% of all Medicare expenditures. For patients covered by Medicare, the ratio of pre- to posttransplant cost of care varied widely by organ and within some organ categories by patient characteristics. This chapter reports pretransplant costs for all solid organ candidates covered by Medicare to allow investigators to further explore the relative cost of transplant compared with alternative management.

OPTN/SRTR 2015 Annual Data Report: Pancreas

The number of pancreas transplants performed in the United States stabilized over the last 3 years after nearly a decade of steady decline. Numbers of new additions to the list also stabilized during the same period. Notably, the persistent decline in pancreas after kidney transplants also seems to have abated, at least for now. The first full year of data after implementation of the new pancreas allocation system revealed no change in the distribution of organs between simultaneous pancreas-kidney (SPK) transplant and pancreas transplant alone. The percentage of kidneys used in SPK transplants was also unchanged. While a uniform definition of pancreas graft failure was approved in June 2015, it is awaiting implementation. Meanwhile, SRTR will refrain from publishing pancreas graft failure data in the program-specific reports. Therefore, it is difficult to track trends in outcomes after pancreas transplant over the past 2 years. New initiatives by the OPTN/UNOS Pancreas Transplantation Committee include facilitated pancreas allocation and broadened allocation of pancreata across compatible ABO blood types to increase organ utilization.

OPTN/SRTR 2015 Annual Data Report: Liver

Several notable developments in adult liver transplantation in the US occurred in 2015. The year saw the largest number of liver transplants to date, leading to reductions in median waiting time, in waitlist mortality for all model for end-stage liver disease categories, and in the number of candidates on the waiting list at the end of the year. Numbers of additions to the waiting list and of liver transplants performed in patients with hepatitis C virus infection decreased for the first time in recent years. However, other diagnoses, such as non-alcoholic fatty liver disease and alcoholic cirrhosis, became more prevalent. Despite large numbers of severely ill patients undergoing liver transplant, graft survival rates continued to improve. The number of new active candidates added to the pediatric liver transplant waiting list in 2015 was 689, down from a peak of 826 in 2005. The number of prevalent pediatric candidates (on the list on December 31 of the given year) continued to decline, to 373 active and 195 inactive candidates. The number of pediatric liver transplants peaked at 613 in 2008 and was 580 in 2015. The number of living donor pediatric liver transplants increased to its highest level, 79, in 2015; most were from donors closely related to the recipients. Pediatric graft survival rates continued to improve.

OPTN/SRTR 2015 Annual Data Report: Lung

In 2015, 2409 active candidates aged 12 years or older were added to the lung transplant waiting list; 2072 transplants were performed, the most of any year. The median waiting time for candidates listed in 2015 was 3.4 months; the shortest waiting time was for diagnosis group D. Despite the highest recorded transplant rate of 157 per 100 waitlist years, waitlist mortality continued a steady decade-long rise to a high of 16.5 deaths per 100 waitlist years. Measures of short- and long-term survival showed no trend toward improved overall survival in the past 5 years, except that 6-month death rates decreased from 9.4% in 2005 to 7.9% in 2014. At 5 years posttransplant, 55.5% of recipients remained alive. In 2015, 23 new child (ages 0-11 years) candidates were added to the list; 17 transplants were performed. Incidence of death was 6.1% at 6 months and 8.2% at 1 year for transplants in 2013-2014. Important policy changes will affect access to transplant. In February 2015, OPTN implemented a comprehensive revision of the lung allocation score to better reflect mortality risk. Broader geographic sharing of donor lungs for pediatric candidates and allowance for selected transplants across blood types for candidates aged younger than 2 years have been approved and are expected to improve pediatric access to transplant. The impact of these changes on lung transplant trends will be observed in the coming years.

OPTN/SRTR 2015 Annual Data Report: Heart

The number of heart transplant candidates and transplants performed continued to rise each year. In 2015, 2819 heart transplants were performed. In addition, the number of new adult candidates on the waiting list increased 51% since 2004. The number of adult heart transplant survivors continued to increase, and in 2015, 29,172 recipients were living with heart transplants. Patient mortality following transplant has declined. The number of pediatric candidates and transplants performed also increased. New listings for pediatric heart transplants increased from 451 in 2004 to 644 in 2015. The number of pediatric heart transplants performed each year increased from 297 in 2004 to 460 in 2015. Among pediatric patients who underwent transplant in 2014, death occurred in 7.2% at 6 months and 9.6% at 1 year.

OPTN/SRTR 2015 Annual Data Report: Intestine

Intestine and intestine-liver transplant remains important in the treatment of intestinal failure, despite decreased morbidity associated with parenteral nutrition. In 2015, 196 new patients were added to the intestine transplant waiting list, with equal numbers waiting for intestine and intestine-liver transplant. Among prevalent patients on the list at the end of 2015, 63.3% were waiting for an intestine transplant and 36.7% were waiting for an intestine-liver transplant. The pretransplant mortality rate decreased dramatically over time for all age groups. Pretransplant mortality was notably higher for intestine-liver than for intestine transplant candidates (respectively, 19.9 vs. 2.8 deaths per 100 waitlist years in 2014-2015). By age, pretransplant mortality was highest for adult candidates, at 19.6 per 100 waitlist years, and lowest for children aged younger than 6 years, at 3.6 per 100 waitlist years. Pretransplant mortality by etiology was highest for candidates with non-congenital types of short-gut syndrome. Numbers of intestine transplants without a liver increased from a low of 51 in 2013 to 70 in 2015. Intestine-liver transplants increased from a low of 44 in 2012 to 71 in 2015. Short-gut syndrome (congenital and non-congenital) was the main cause of disease leading to intestine and to intestine-liver transplant. Patient survival was lowest for adult intestine-liver recipients and highest for pediatric intestine recipients.

OPTN/SRTR 2015 Annual Data Report: Deceased Organ Donation

SRTR uses data collected by OPTN to calculate metrics such as donation/conversion rate, organ yield, and rate of organs recovered for transplant but not transplanted. In 2015, 1,072,828 death and imminent death referrals were made to Organ Procurement Organizations, of which 21,559 met the definition of eligible (9793) or imminent (11,766) deaths per OPTN policy. The number of deceased donors was 9080, and this number has been increasing since 2010. The number of organs authorized for recovery increased slightly to 65,086 in 2015, and the number recovered increased slightly to 25,762. In 2015, 4370 organs were discarded, including 3157 kidneys, 311 pancreata, 703 livers, 30 hearts, and 214 lungs. These numbers suggest a need to reduce the number of organs discarded.

Potential Implications of Recent and Proposed Changes in the Regulatory Oversight of Solid Organ Transplantation in the United States

Every 6 months, the Scientific Registry of Transplant Recipients (SRTR) publishes evaluations of every solid organ transplant program in the United States, including evaluations of 1-year patient and graft survival. The Centers for Medicare & Medicaid Services (CMS) and the Organ Procurement and Transplantation Network (OPTN) Membership and Professional Standards Committee (MPSC) use SRTR's 1-year evaluations for regulatory review of transplant programs. Concern has been growing that the regulatory scrutiny of transplant programs with lower-than-expected outcomes is harmful, causing programs to undertake fewer high-risk transplants and leading to unnecessary organ discards. As a result, CMS raised its threshold for a "Condition-Level Deficiency" designation of observed relative to expected 1-year graft or patient survival from 1.50 to 1.85. Exceeding this threshold in the current SRTR outcomes report and in one of the four previous reports leads to scrutiny that may result in loss of Medicare funding. For its part, OPTN is reviewing a proposal from the MPSC to also change its performance criteria thresholds for program review, to review programs with "substantive clinical differences." We review the details and implications of these changes in transplant program oversight.

HLA and Risk of Diffuse Large B cell Lymphoma After Solid Organ Transplantation

BACKGROUND

Solid organ transplant recipients have heightened risk for diffuse large B cell lymphoma (DLBCL). The role of donor-recipient HLA mismatch and recipient HLA type on DLBCL risk are not well established.

METHODS

We examined 172 231 kidney, heart, pancreas, and lung recipients transplanted in the United States between 1987 and 2010, including 902 with DLBCL. Incidence rate ratios (IRRs) were calculated using Poisson regression for DLBCL risk in relation to HLA mismatch, types, and zygosity, adjusting for sex, age, race/ethnicity, year, organ, and transplant number.

RESULTS

Compared with recipients who had 2 HLA-DR mismatches, those with zero or 1 mismatch had reduced DLBCL risk, (zero: IRR, 0.76, 95% confidence interval [95% CI], 0.61-0.95; one: IRR, 0.83; 95% CI, 0.69-1.00). In stratified analyses, recipients matched at either HLA-A, -B, or -DR had a significantly reduced risk of late-onset (>2 years after transplantation), but not early-onset DLBCL, and there was a trend for decreasing risk with decreasing mismatch across all 3 loci (P = 0.0003). Several individual recipient HLA-A, -B, -C, -DR, and -DQ antigens were also associated with DLBCL risk, including DR13 (IRR, 0.74; 95% CI, 0.57-0.93) and B38 (IRR, 1.48; 95% CI, 1.10-1.93), confirming prior findings that these 2 antigens are associated with risk of infection-associated cancers.

CONCLUSIONS

In conclusion, variation in HLA is related to susceptibility to DLBCL, perhaps reflecting intensity of immunosuppression, control of Epstein-Barr virus infection among transplant recipients or chronic immune stimulation.

Abnormalities in biomarkers of mineral and bone metabolism in kidney donors

Previous studies have suggested that kidney donors may have abnormalities of mineral and bone metabolism typically seen in chronic kidney disease. This may have important implications for the skeletal health of living kidney donors and for our understanding of the pathogenesis of long-term mineral and bone disorders in chronic kidney disease. In this prospective study, 182 of 203 kidney donors and 173 of 201 paired normal controls had markers of mineral and bone metabolism measured before and at 6 and 36 months after donation (ALTOLD Study). Donors had significantly higher serum concentrations of intact parathyroid hormone (24.6% and 19.5%) and fibroblast growth factor-23 (9.5% and 8.4%) at 6 and 36 months, respectively, as compared to healthy controls, and significantly reduced tubular phosphate reabsorption (-7.0% and -5.0%) and serum phosphate concentrations (-6.4% and -2.3%). Serum 1,25-dihydroxyvitamin D3 concentrations were significantly lower (-17.1% and -12.6%), while 25-hydroxyvitamin D (21.4% and 19.4%) concentrations were significantly higher in donors compared to controls. Moreover, significantly higher concentrations of the bone resorption markers, carboxyterminal cross-linking telopeptide of bone collagen (30.1% and 13.8%) and aminoterminal cross-linking telopeptide of bone collagen (14.2% and 13.0%), and the bone formation markers, osteocalcin (26.3% and 2.7%) and procollagen type I N-terminal propeptide (24.3% and 8.9%), were observed in donors. Thus, kidney donation alters serum markers of bone metabolism that could reflect impaired bone health. Additional long-term studies that include assessment of skeletal architecture and integrity are warranted in kidney donors.

Comparison of Cancer Diagnoses Between the US Solid Organ Transplant Registry and Linked Central Cancer Registries

US transplant centers are required to report cancers in transplant recipients to the transplant network. The accuracy and completeness of these data, collected in the Scientific Registry of Transplant Recipients (SRTR), are unknown. We compared diagnoses in the SRTR and 15 linked cancer registries for colorectal, liver, lung, breast, prostate and kidney cancers; melanoma; and non-Hodgkin lymphoma (NHL). Among 187 384 transplants, 9323 cancers were documented in the SRTR or cancer registries. Only 36.8% of cancers were in both, with 47.5% and 15.7% of cases additionally documented solely in cancer registries or the SRTR, respectively. Agreement between the SRTR and cancer registries varied (kappa = 0.28 for liver cancer and kappa = 0.52-0.66 for lung, prostate, kidney, colorectum, and breast cancers). Upon evaluation, some NHLs documented only in cancer registries were identified in the SRTR as another type of posttransplant lymphoproliferative disorder. Some SRTR-only cases were explained by miscoding (colorectal cancer instead of anal cancer, metastases as lung or liver cancers) or missed matches with cancer registries, partly due to recipients' outmigration from catchment areas. Estimated sensitivity for identifying cancer was 52.5% for the SRTR and 84.3% for cancer registries. In conclusion, SRTR cancer data are substantially incomplete, limiting their usefulness for surveillance and research.

Effects of High-Risk Kidneys on Scientific Registry of Transplant Recipients Program Quality Reports

There is a perception that transplanting high-risk kidneys causes programs to be identified as underperforming, thereby increasing the frequency of discards and diminishing access to transplant. Thus, the Organ Procurement and Transplantation Network (OPTN) has considered excluding transplants using kidneys from donors with high Kidney Donor Profile Index (KDPI) scores (≥0.85) when assessing program performance. We examined whether accepting high-risk kidneys (KDPI ≥0.85) for transplant yields worse outcome evaluations. Despite a clear relationship between KDPI and graft failure and mortality, there was no relationship between a program's use of high-KDPI kidneys and poor performance evaluations after risk adjustment. Excluding high-KDPI donor transplants from the June 2015 evaluations did not alter the programs identified as underperforming, because in every case underperforming programs also had worse-than-expected outcomes among lower-risk donor transplants. Finally, we found that hypothetically accepting and transplanting additional kidneys with KDPI similar to that of kidneys currently discarded would not adversely affect program evaluations. Based on the study findings, there is no evidence that programs that accept higher-KDPI kidneys are at greater risk for low performance evaluations, and risk aversion may limit access to transplant for candidates while providing no measurable benefit to program evaluations.

The clinical relevance of Organ Procurement and Transplantation Network screening criteria for program performance review in the United States

The Organ Procurement and Transplantation Network is charged with overseeing the quality of transplant programs in the United States. However, there has been controversy over whether too many programs are being identified as underperforming. It has also been suggested that dramatic improvements in outcomes throughout the United States have made the thresholds for determining which deceased donor transplant programs are underperforming no longer clinically relevant. The Scientific Registry of Transplant Recipients compared actual and expected 1-y graft survival for transplant programs identified as underperforming in the most recent cohort (transplants from July 1, 2012 to December 31, 2014). For most organs, actual 1-y graft survival was substantially lower for programs identified as underperforming than for programs identified as performing as expected. Differences were smallest for kidney programs: median 1-y graft survival 89.2% vs 95.4% in large-volume programs identified and not identified for Membership and Professional Standards Committee review, respectively. Median expected graft survival was only slightly lower (94.8% vs 95.1%, respectively), suggesting that identified and not identified programs tend to have similar risk tolerances. An excess of 143 grafts were lost from kidney programs identified as underperforming. Transplant programs identified as underperforming generally have reduced 1-y graft survival that stakeholders may consider clinically relevant.

Smoking and Adverse Outcomes in Patients With CKD: The Study of Heart and Renal Protection (SHARP)

Background

The absolute and relative importance of smoking to vascular and nonvascular outcomes in people with chronic kidney disease (CKD), as well its relevance to kidney disease progression, is uncertain.

Study Design

Observational study.

Setting & Participants

9,270 participants with CKD enrolled in SHARP.

Predictor

Baseline smoking status (current, former, and never).

Outcomes

Vascular events, site-specific cancer, ESRD, rate of change in estimated glomerular filtration rate (eGFR), and cause-specific mortality.

Results

At baseline, 1,243 (13%) participants were current smokers (median consumption, 10 cigarettes/day); 3,272 (35%), former smokers; and 4,755 (51%), never smokers. Median follow-up was 4.9 years. Vascular event rates were 36% higher for current than never smokers (2,317 events; relative risk [RR], 1.36; 95% CI, 1.19-1.55), reflecting increases in both atherosclerotic (RR, 1.49; 95% CI, 1.26-1.76) and nonatherosclerotic (RR, 1.25; 95% CI, 1.05-1.50) events. Cancer was 37% higher among current smokers (632 events; RR, 1.37; 95% CI, 1.07-1.76), with the biggest RRs for lung (RR, 9.31; 95% CI, 4.37-19.83) and upper aerodigestive tract (RR, 4.87; 95% CI, 2.10-11.32) cancers. For 6,245 patients not receiving dialysis at baseline, ESRD incidence did not differ significantly between current and never smokers (2,141 events; RR, 1.02; 95% CI, 0.89-1.17), nor did estimated rate of change in eGFR (current smokers, −1.77 ± 0.14 [SE]; never smokers, −1.70 ± 0.07 mL/min/1.73 m² per year). All-cause mortality was 48% higher among current smokers (2,257 events; RR, 1.48; 95% CI, 1.30-1.70), with significant increases in vascular (RR, 1.35; 95% CI, 1.07-1.69) and nonvascular (RR, 1.60; 95% CI, 1.34-1.91) causes of death, especially cancer (RR, 2.32; 95% CI, 1.58-3.40) and respiratory (RR, 2.25; 95% CI, 1.51-3.35) mortality.

Limitations

Smoking status not assessed during follow-up.

Conclusions

In this study of patients with CKD, smoking significantly increased the risks for vascular and nonvascular morbidity and mortality, but was not associated with kidney disease progression. The associations with vascular and neoplastic disease are in keeping with those observed in the general population and are likely modifiable by cessation.