Clustering and Healthcare Costs With Multiple Chronic Conditions in a US Cross-Sectional Study
Authors: Hajat C , Siegal Y , Adler-Waxman Amalia 
Published: August 2020

AbstractObjectiveTo investigate healthcare costs and contributors to costs for multiple chronic conditions (MCCs), common clusters of conditions and their impact on cost and utilisation.MethodsThis was a cross-sectional analysis of US financial claims data representative of the US population, including Medicare, Medicaid and Commercial insurance claims in 2015. Outcome measures included healthcare costs and contributors; ranking of clusters of conditions according to frequency, strength of association and unsupervised (k-means) analysis; the impact of clustering on costs and contributors to costs.ResultsOf 1,878,951 patients, 931,045(49.6%) had MCCs, 56.5% weighted to the US population. Mean age was 53.0 years(SD16.7); 393,121(42.20%) were male. Mean annual healthcare spending was $12,601, ranging from $4,385 (2 conditions) to $33,874 (11 conditions), with spending increasing by 22-fold for inpatient services, 6-fold for outpatient services, 4.5-fold for generic drugs and 4.2-fold for branded drugs.Cluster ranking using the 3 methodologies yielded similar results: highest ranked clusters included metabolic syndrome(12.2% of US insured patients), age related diseases(7.7%), renal failure(5.6%), respiratory disorders(4.5%), cardiovascular disease(CVD)(4.3%), cancers(4.1-4.3%), mental health-related clusters(1.0-1.5%) and HIV/AIDS(0.2%).Highest spending was in HIV/AIDS clusters ($48,293), mental health-related clusters ($38,952-$40,637), renal disease ($38,551) and CVD ($37,155); with 89.9% of spending on outpatient and inpatient care combined, and 10.1% on medication.Conclusion and RelevanceOver 57% of insured patients in the US may have MCCs. MCC Clustering is frequent and is associated with healthcare utilisation. The findings favour health system redesign towards a multiple condition approach for clusters of chronic conditions, alongside other cost-containment measures for MCCs.HighlightsWhat is already known about the topic?Despite one in three adults suffering from more than one chronic condition, little is known about the burden from MCCs. Some studies to date suggest markedly different disease, cost and societal burdens. Furthermore, certain conditions cluster together more frequently, however, no studies have reported on the impact that clusters have on the healthcare cost burden from MCCs in a comprehensive manner. Recent consensus statements have called for a specific focus on multiple chronic conditions.What does the paper add to existing knowledge?This study is one of the most comprehensive studies investigating contributors to costs in terms of number of patients included, representativeness of the US population and inclusion of the full range of chronic conditions.What insights does the paper provide for informing healthcare-related decision making?Of US insured patients, over 57% may have multiple chronic conditions.HIV/AIDS was the costliest cluster followed by clusters of mental and behavioural disorders, renal failure and CVD. Outpatient and inpatient services account for roughly 90% of health spending and medication for 10%.Health service utilisation varies by number and clusters of conditions, with potential overutilization of specialist services and underutilisation of primary care and psychiatric services.