Thrombocytopenia predicts mortality in Chinese hemodialysis patients- an analysis of the China DOPPS

Abstract

Background: Hemodialysis (HD) patients have a higher mortality rate compared with general population. Our previous study revealed that platelet counts might be a potential risk factor. The role of platelets in HD patients has rarely been studied. The aim of this study is to examine if there is an association of thrombocytopenia (TP) with elevated risk of all-cause mortality and cardiovascular (CV) death in Chinese HD patients.

Methods: Data from a prospective cohort study, China Dialysis Outcomes and Practice Patterns Study (DOPPS) 5, were analyzed. Demographic data, comorbidities, platelet counts and other lab data, and death records which extracted from the medical record were analyzed. TP was defined as the platelet count below the lower normal limit (< 100*10⁹/L). Associations between platelet counts and all-cause and CV mortality were evaluated using Cox regression models. Stepwise multivariate logistic regression was used to identify the independent associated factors, and subgroup analyses were also carried out.

Results: Of 1369 patients, 11.2% (154) had TP at enrollment. The all-cause mortality rates were 26.0% vs. 13.3% (p < 0.001) in patients with and without TP. TP was associated with higher all-cause mortality after adjusted for covariates (HR:1.73,95%CI:1.11,2.71), but was not associated with CV death after fully adjusted (HR:1.71,95%CI:0.88,3.33). Multivariate logistic regression showed that urine output < 200 ml/day, cerebrovascular disease, hepatitis (B or C), and white blood cells were independent impact factors (P < 0.05). Subgroup analysis found that the effect of TP on all-cause mortality was more prominent in patients with diabetes or hypertension, who on dialysis thrice a week, with lower ALB (< 4 g/dl) or higher hemoglobin, and patients without congestive heart failure, cerebrovascular disease, or hepatitis (P < 0.05).

Conclusion: In Chinese HD patients, TP is associated with higher risk of all-cause mortality, but not cardiovascular mortality. Platelet counts may be a useful prognostic marker for clinical outcomes among HD patients, though additional study is needed.

Keywords: Cardiovascular death; DOPPS; Hemodialysis; Mortality; Thrombocytopenia.

Fig. 1

The Kaplan-Meier curves for TP and Non-TP groups in HD patients. A Survival curves of all-cause mortality; B Survival curves of CV mortality between two groups. Abbreviations: HD hemodialysis; TP thrombocytopenia; Non-TP without thrombocytopenia

Fig. 2

Associations between the platelet counts and all-cause mortality and CV mortality in different Cox regression models. Notes: Model 1: unadjusted; model 2: adjusted for age, gender, BMI, vintage; model 3: model 2 variables plus comorbidities (diabetes, coronary artery disease, congestive heart failure, other cardiovascular disease, cerebrovascular disease, hepatitis B and C, cancer (non-skin), peripheral vascular disease, lung disease, hypertension, psychiatric disorder, GI Bleeding, recurrent cellulitis, fracture, neurologic disease).; model 4: model 3 plus hemoglobin, albumin, white blood cells, and serum creatinine; model 5: model 4 plus Intradialytic weight loss, fistula use, primary kidney disease, standard kt/v, urine output < 200 ml/d. Abbreviations: TP thrombocytopenia; Non-TP without thrombocytopenia

Fig. 3

Association of thrombocytopenia with all-cause mortality across clinically relevant subgroups