Comorbidities and ethnic health disparities in the UK biobank

Abstract

Objective: The goal of this study was to investigate the relationship between comorbidities and ethnic health disparities in a diverse, cosmopolitan population.

Materials and methods: We used the UK Biobank (UKB), a large progressive cohort study of the UK population. Study participants self-identified with 1 of 5 ethnic groups and participant comorbidities were characterized using the 31 disease categories captured by the Elixhauser Comorbidity Index. Ethnic disparities in comorbidities were quantified as the extent to which disease prevalence within categories varies across ethnic groups and the extent to which pairs of comorbidities co-occur within ethnic groups. Disease-risk factor comorbidity pairs were identified where one comorbidity is known to be a risk factor for a co-occurring comorbidity.

Results: The Asian ethnic group shows the greatest average number of comorbidities, followed by the Black and then White groups. The Chinese group shows the lowest average number of comorbidities. Comorbidity prevalence varies significantly among the ethnic groups for almost all disease categories, with diabetes and hypertension showing the largest differences across groups. Diabetes and hypertension both show ethnic-specific comorbidities that may contribute to the observed disease prevalence disparities.

Discussion: These results underscore the extent to which comorbidities vary among ethnic groups and reveal group-specific disease comorbidities that may underlie ethnic health disparities.

Conclusion: The study of comorbidity distributions across ethnic groups can be used to inform targeted group-specific interventions to reduce ethnic health disparities.

Keywords: Elixhauser Comorbidity Index; UK Biobank; comorbidity; ethnic health disparity; health equity.

Figure 1.

Distribution of Elixhauser Comorbidity Index (ECI) scores in the UKBB. Main panel: Distribution of ECI scores for ECI ≥ 1. Inset: Distribution of all ECI scores.

Figure 2.

Distribution of Elixhauser Comorbidity Index (ECI) scores for UKBB ethnic groups. (A) Average ECI score for each of the ethnic groups. (B) Frequency (y axis) of each ECI scores ≥1 (x axis) for each ethnic group.

Figure 3.

Relative Comorbidity Index (RCI) for ECI disease categories across the ethnic groups in the UKBB. RCI values for each ECI disease category are shown across ethnic groups (color coded as shown in the RCI key). Statistical significance values for the variation of RCI (FDR q value) are shown on the right.

Figure 4.

Ethnic group-specific networks for comorbid disease pairs. For each ethnicity (Asian-red, top network, Black-blue, middle network, and White-orange, bottom network), a network of significantly co-occurring pairs of comorbidities is shown. Each comorbid disease is represented as a node in the network; nodes are scaled based on the prevalence of the comorbid disease in the ethnic group. Nodes are connected if they have a significant G-test FDR q value; edge lengths represent the differences in observed and expected comorbidity pairs; edge weight represent the fold-change value of the comorbidity pair when compared across the 3 ethnicities.

Figure 5.

Ethnic group-specific risk factors for comorbid disease pairs. The relationship between comorbidities as risk factors (green boxes) is shown overlaid on the presence/absence of significant comorbid disease pairs (gray boxes) for each ethnic group (Asian, Black, and White). Risk factors are indicated on the x axis and the disease categories that they affect are indicated on the y axis. Comorbidities are categorized into categories as shown.