Prevalence, patterns, and impacts of multimorbidity on adverse clinical outcomes in chronic kidney disease: A systematic review

Abstract

Background: Multimorbidity is the concurrent presence of two or more long-term health conditions in the same individual. It fragments healthcare delivery and affects quality of life. Chronic kidney disease (CKD) often occurs with multimorbidity. The prevalence of CKD is rising; however, there is a lack of evidence on the prevalence, patterns, and impacts of multimorbidity on adverse clinical outcomes in patients with CKD.
 Methods: This was a systematically conducted literature review. A search was conducted in EMBASE, MEDLINE, CINAHL, and SCOPUS (2019-2023). The main search terms were “chronic kidney disease” and “multimorbidity.” The eligibility criteria were observational studies with adult participants with all stages of CKD (CKD stages 1-5, including those on renal replacement therapy). The exposure was multimorbidity quantified by measures. All-cause mortality, kidney disease progression, hospitalisation, and cardiovascular events were outcomes. The Joanna Briggs Institute (JBI) checklist was used for the risk of bias assessment. Due to heterogeneity in design and methods, Jennie Popay’s narrative synthesis was used for data synthesis.
 Results: Of 6879 papers, nine papers met the inclusion criteria. Most studies included participants with all stages of CKD (CKD stage 1-5). The prevalence of multimorbidity ranged from 86.6% to 99.1%. Hypertension was the most prevalent comorbidity. The combination of concordant multimorbidity (hypertension, diabetes, and cardiovascular diseases) was highly prevalent. Multimorbidity was significantly associated with mortality, cardiovascular events, kidney disease progression, and hospitalisation. While older people had more multimorbidity burdens, younger patients with CKD were at a higher risk of death from multimorbidity. Severe CKD with clusters of cardiovascular diseases, diabetes, chronic pain, and depression was significantly associated with all-cause mortality.
 Conclusion: There are associations between multimorbidity and adverse clinical outcomes in patients with CKD. However, there is a lack of data on Black, Asian, and Minority Ethnic participants from low- and middle-income countries. Further research is needed to investigate the high prevalence of chronic pain and depression in chronic kidney disease.