Protocol for the Study of Heart and Renal Protection-Extended Review: Additional 5-Year Follow-up of the Australian, New Zealand, and Malaysian SHARP Cohort

HMG CoA reductase inhibitors (statins) for people with chronic kidney disease not requiring dialysis

BACKGROUND

Cardiovascular disease is the most frequent cause of death in people with early stages of chronic kidney disease (CKD), and the absolute risk of cardiovascular events is similar to people with coronary artery disease. This is an update of a review first published in 2009 and updated in 2014, which included 50 studies (45,285 participants).

OBJECTIVES

To evaluate the benefits and harms of statins compared with placebo, no treatment, standard care or another statin in adults with CKD not requiring dialysis.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 4 October 2023. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov. An updated search will be undertaken every three months.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of statins with placebo, no treatment, standard care, or other statins, on death, cardiovascular events, kidney function, toxicity, and lipid levels in adults with CKD (estimated glomerular filtration rate (eGFR) 90 to 15 mL/min/1.73 m2) were included.

DATA COLLECTION AND ANALYSIS

Two or more authors independently extracted data and assessed the study risk of bias. Treatment effects were expressed as mean difference (MD) for continuous outcomes and risk ratios (RR) for dichotomous benefits and harms with 95% confidence intervals (CI). The risk of bias was assessed using the Cochrane risk of bias tool, and the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 63 studies (50,725 randomised participants); of these, 53 studies (42,752 participants) compared statins with placebo or no treatment. The median duration of follow-up was 12 months (range 2 to 64.8 months), the median dosage of statin was equivalent to 20 mg/day of simvastatin, and participants had a median eGFR of 55 mL/min/1.73 m2. Ten studies (7973 participants) compared two different statin regimens. We were able to meta-analyse 43 studies (41,273 participants). Most studies had limited reporting and hence exhibited unclear risk of bias in most domains. Compared with placebo or standard of care, statins prevent major cardiovascular events (14 studies, 36,156 participants: RR 0.72, 95% CI 0.66 to 0.79; I2 = 39%; high certainty evidence), death (13 studies, 34,978 participants: RR 0.83, 95% CI 0.73 to 0.96; I² = 53%; high certainty evidence), cardiovascular death (8 studies, 19,112 participants: RR 0.77, 95% CI 0.69 to 0.87; I² = 0%; high certainty evidence) and myocardial infarction (10 studies, 9475 participants: RR 0.55, 95% CI 0.42 to 0.73; I² = 0%; moderate certainty evidence). There were too few events to determine if statins made a difference in hospitalisation due to heart failure. Statins probably make little or no difference to stroke (7 studies, 9115 participants: RR 0.64, 95% CI 0.37 to 1.08; I² = 39%; moderate certainty evidence) and kidney failure (3 studies, 6704 participants: RR 0.98, 95% CI 0.91 to 1.05; I² = 0%; moderate certainty evidence) in people with CKD not requiring dialysis. Potential harms from statins were limited by a lack of systematic reporting. Statins compared to placebo may have little or no effect on elevated liver enzymes (7 studies, 7991 participants: RR 0.76, 95% CI 0.39 to 1.50; I² = 0%; low certainty evidence), withdrawal due to adverse events (13 studies, 4219 participants: RR 1.16, 95% CI 0.84 to 1.60; I² = 37%; low certainty evidence), and cancer (2 studies, 5581 participants: RR 1.03, 95% CI 0.82 to 1.30; I² = 0%; low certainty evidence). However, few studies reported rhabdomyolysis or elevated creatinine kinase; hence, we are unable to determine the effect due to very low certainty evidence. Statins reduce the risk of death, major cardiovascular events, and myocardial infarction in people with CKD who did not have cardiovascular disease at baseline (primary prevention). There was insufficient data to determine the benefits and harms of the type of statin therapy.

AUTHORS' CONCLUSIONS

Statins reduce death and major cardiovascular events by about 20% and probably make no difference to stroke or kidney failure in people with CKD not requiring dialysis. However, due to limited reporting, the effect of statins on elevated creatinine kinase or rhabdomyolysis is unclear. Statins have an important role in the primary prevention of cardiovascular events and death in people who have CKD and do not require dialysis. Editorial note: This is a living systematic review. We will search for new evidence every three months and update the review when we identify relevant new evidence. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Comparing survival in patients with chronic kidney disease across three countries - Results from the study of heart and renal protection-extended review

AIM

This study examined whether survival and causes of death differed between participants enrolled from Australia (AUS), Malaysia (MYL), and New Zealand (NZ) in extended follow-up of the Study of Heart and Renal Protection (SHARP), a randomized controlled trial (RCT) of participants with moderate to severe chronic kidney disease comparing placebo to combination therapy with Simvastatin and Ezetimibe.

METHODS

All participants alive at final SHARP study visit in participating centres were eligible for inclusion. Consenting participants were re-enrolled following final SHARP Study visit and followed for 5 years. Data collection included: significant medical events, hospital admissions and requirement for kidney replacement therapy. Data linkage was performed to national kidney and mortality registries. The primary outcome was all-cause mortality compared across the three countries.

RESULTS

The SHARP trial randomized 2029 participants from AUS (1043/2029, 51%), MYL (701/2029, 35%), and NZ (285/2029, 14%), with 1136 participants alive and eligible for extended follow-up at the end of SHARP. In multivariable analysis, risk of death was increased for participants in MYL (HR 1.37, 95% CI 1.17-1.61, p < .001) and NZ (HR 1.28, 95% CI 1.04-1.57, p = .02) when compared to AUS participants. Adjustment for kidney transplantation as a competing risk did not explain the variation seen between countries.

CONCLUSION

This study allows a better understanding of the differences in long-term mortality risk across participants from AUS, MYL, and NZ in extended follow-up of the SHARP study and demonstrates the feasibility and value of extended follow-up of participants enrolled in RCTs.

Concepts and Controversies: Lipid Management in Patients with Chronic Kidney Disease

Atherosclerotic cardiovascular disease (ASCVD) remains an important contributor of morbidity and mortality in patients with chronic kidney disease (CKD). CKD is recognized as an important risk enhancer that identifies patients as candidates for more intensive low-density lipoprotein (LDL) cholesterol lowering. However, there is controversy regarding the efficacy of lipid-lowering therapy, especially in patients on dialysis. Among patients with CKD, not yet on dialysis, there is clinical trial evidence for the use of statins with or without ezetimibe to reduce ASCVD events. Newer cholesterol lowering agents have been introduced for the management of hyperlipidemia to reduce ASCVD, but these therapies have not been tested in the CKD population except in secondary analyses of patients with primarily CKD stage 3. This review summarizes the role of hyperlipidemia in ASCVD and treatment strategies for hyperlipidemia in the CKD population.