(A) Prevalence of 17 broad disease classes as per Charlson’s comorbidity classification. (B) Heatmap showing the co-occurrence of 17 broad disease classes as per Charlson’s comorbidity classification. Order of disease from top to bottom and left to right are myocardial infraction (MI), congestive heart failure (CHF), peripheral vascular disease (PVD), stroke, dementia, pulmonary disease, rheumatic disease, peptic ulcer disease (PUD), mild liver disease (LiverMild), diabetes mellitus (DM), DM with chronic complications (DMcx), paralysis, renal disease, cancer, severe liver disease (LiverSevere), metastasis and HIV. Darker shade represents higher co-occurrence.