Haematological Indices and Anaemia in Patients with Type 2 Diabetes Mellitus: Systematic Review and Meta-Analysis

Abstract

The objective of this paper is to systematically review and meta-analyse the relationship between haematological indices, anaemia and their significance in patients with type 2 diabetes mellitus (T2DM). A search of studies was conducted in the main databases (Medline, PubMed, EMBASE and Google Scholar) and the reference lists of selected studies. Comparative cross-sectional and case-control studies that met the eligibility criteria were included in this meta-analysis. There was no limitation in terms of language. Two independent researchers performed study selection and data extraction. Meta-analyses with random, fixed-effects model and subgroup analyses were performed. Publication bias was visualised by funnel plots. Quality of studies was evaluated following modified Downs and Black guideline. A total of 79 studies were retrieved, and 13 were included in the meta-analyses. The glucose metabolic profiles were higher in T2DM in relative to control (standardised mean difference (SMD) = 0.85, 95% CI (0.64; 1.06), p < 0.00001). However, there was reduction in haematological indices (SMD = − 0.52, 95% CI (− 0.78; − 0.25), p = 0.0001), both reticulocyte and erythropoietin, (SMD = − 1.33, 95% CI (− 2.23; − 0.44), p = 0.003), iron profiles (SMD = − 1.38 (− 2.08; − 0.67), p = 0.00001) and total-iron binding capacity (mean difference (MD) = − 44.88 (− 45.75, − 43.98), p < 0.00001) in T2DM patient relative to control. Meta-analysis results suggest that T2DM patients develop anaemia as a result of reduced erythropoietin, reticulocytes, haemoglobin, haematocrit, mean cell volume and iron profiles.