| BackgroundChronic kidney disease is gradually becoming an important public health problem. Speaking of chronic kidney disease, we always associate it with the harmful outcome it induces and the huge medical expenses it brings about. Risk factors of chronic kidney disease progression are similar to those of cardiovascular disease, including hypertension, diabetes, dyslipidemia and so on. Cardiovascular disease is becoming the leading cause of morbidity and mortality in patients with chronic kidney disease. They are susceptible to get cardiovascular diseases which may induce a decline in kidney function. As with the outcome of cardiovascular events, the outcome of patients with chronic kidney disease can be improved by BP reduction, tight glycemic control, intervention of the renin/angiotensin system and smoking cessation. Despite of those therapeutic measures mentioned above, the disease would still progress. We still need new medical strategy to preserve kidney function.Patients with chronic kidney disease are at high risks of cardiovascular disease. Kidney Disease Outcome Quality Initiative (K/DOQI) recommends that CKD patients with a high serum LDL level use statins to prevent cardiovascular disease. Despite the cardiovascular benefit that statins bring about, large-scale trials and systematic studies are still lacking on effect of statins on the prevention of cardiovascular events and improvement of kidney outcome in patients with chronic kidney disease. There are lots of different and contradictory results reported in existing studies, especially those related to end-stage kidney disease.The lipid concentration curve in patients with chronic kidney disease does not look like cardiovascular events curve that we observe in public people. As a matter of fact, in many studies, dialysis patients with the lowest LDL level are more likely to have the worst outcome. In patients with severe kidney insufficiency, atherosclerosis is not fully responsible for cardiovascular disease compared to people with normal kidney function. Recent studies indicate that the cardiovascular pathology of patients with progressive chronic kidney disease may be different from that of common people. The growing risk of arrhythmia and heart failure may be responsible for the vascular sclerosis and calcification, cardiac reconstruction, overexcitation of sympathetic nerve in those patients. This is why we rarely estimate the effect of statin therapy in CKD patients compared to public population. In the past few years, several large clinical trials focused on the effect of statin therapy in patients with chronic kidney disease are finished. Some show positive effect, but some indicate no superiority, which leads to a controversy on whether statin therapy can benefit renal function in CKD patients, thus clinicians feel confused when they have to make a decision. This meta analysis is aimed to collect all the available data to assess the effect of statin therapy on kidney function in patients with chronic kidney diseaseObjectiveThis meta-analysis is aimed to evaluate the effect of statin therapy on protect kidney function in patients with chronic kidney disease and whether this effect relies on the duration of the treatment, which is intended to provide EBM evidence for reasonable clinical application of statins.MethodsWe searched Medline, EMBASE, Cochrane Library and also related references to collect as many studies as possible. Studies that mentioned data on kidney function of CKD patients, published and unpublished, randomized clinical trials and crossover trials, were included, inclusion criteria and exclusion criteria taken into account. P value and I2were used to test heterogeneity. Then the statistical model was decided based on the value we got. Subgroup analyses were made about those factors that may influence the results.ResultsThis meta-analysis included17studies and1982patients. We used fixed effect model to calculate the standard mean difference of eGFR. On the whole, the standard mean difference of eGFR change in CKD patients comparing statin group with controlled group was statistically significant(0.11ml/min,95%CI:[0.02,0.20], P=0.01). In subgroup analysis, the standard mean difference of eGFR change in CKD patients with longer treatment duration (>6mon) comparing statin group with controlled group was statistically significant(0.12ml/min,95%CI:[0.01,0.22], P=0.03). However, the standard mean difference of eGFR change in CKD patients with short-term therapy(≤6mon) comparing statin group with controlled group was not statistically significant(0.10ml/min,95%CI:[-0.06,0.26], P=0.21). In other subgroup, patients in CKD stage1to4, benefit more with statin treatment when their LDL-C level are more than3.38mmol/L (0.12ml/min,95%IC:[0.01,0.23], P=0.03)。Compared to CKD (Stage1to4) patients caused by diabetes, patients with glomerular nephritis are more likely to get more benefit of kidney function preservation from statins(0.69ml/min,95%CI:[0.29,1.10], P=0.0008). In UPE subgroup analysis, we did not get positive effect of statin group.ConclusionStatin therapy may slow down the progression of patients with mild to moderate chronic kidney disease. However, benefit may depend on the duration of treatment. CKD patients (Stage1to4) are more likely to get kidney benefit with longer treatment (>6mon) of statins. While no similar benefit is observed in short-term treatment(≤6mon). patients in CKD stage1to4, benefit more with statin treatment when their LDL-C level are more than3.38mmol/L. Beside, it seems that patients with CKD caused by GN are more likely to benefit from statin treatment.This is an issue that warrants more definitive investigation. Despite the results found in this meta-analysis, the limitation of the methodology makes the author realize that new large RCTs are still needed to provide more clear and definite evidence for the relationship between statin and its kidney bebefit in CKD patients. |
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