Summary of multimorbidity instruments and their associations with outcomes measured from all the included studies
| Multimorbidity measures | Association between outcomes and multimorbidity | |
| Evidence of an association | No evidence of an association | |
| A=Count of individual conditions | ||
| DC (many different groupings ranging from 764 76 113 to 14766 conditions and some are further categorised21) | ADL limitations,43 activity limitations,52 affective well-being,126 cognitive function,82 continuity of care (3 years),105 deficits of perceived general health,104 depression,92 depressive symptoms,67 104 disability,17 65 84 85 emergency hospital admission (2 years),120 fall-related injuries,71 fall risk,76 frequency of contacts with physicians (1 year),116 functional capacity,93 functional decline (2 years),120 functional Impairment,111 functional limitations,74 future physical functioning,28 general health,52 healthcare costs,23 91 health-related quality of life,68 75 81 90 115 hospitalisation (3 years),18 hospital admissions (1 year),95 96 99 hospital outpatient visits (1 year),114 hospitalisation/emergency department visits,114 life satisfaction,22 mental distress,52 mortality (1 year),99 (3 years),18 48 (5 years),110 (10 years),28 number of contacts with general practice (1 year),117 number of medications prescribed (1 year),117 number of mentally unhealthy days,43 44 number of physically unhealthy days,43 44 number of different ambulatory physicians contacted (1 year),116 number of primary care consultations (1 year),48 (3 years),48 number of referrals (1 year),117 outpatient/Inpatient service use,53 physical distress,52 physical function,55 prescription costs,70 perceived health status,22 presence of mental health disorder,66 primary care consultations (1 year period),105 (3 years),105 primary care experience—self-reported,83 primary healthcare cost,47 primary healthcare use,89 potentially preventable unplanned admission (1-year period),95 quality-adjusted life years,72 73 quality of life,93 98 101 102 self-rated health,118 self-reported falls (12 months),108 symptom burden,101 self-rated Health,64 85 self-perceived health,93 total number of consultation,42 total health care costs42 | Functional decline,18 quality of cardiovascular preventive care,27 quality of preventive care27 |
| CCC | Healthcare costs,21 hospital admissions (1 year),21 number of emergency department visits (1 year),21 readmission within 30 days (1 year)21 | |
| B=Organ or system-based approaches | ||
| Organ systems with CDC | Presence of depressive or anxiety disorder19 | |
| CIRS | Disability,17 frailty,17 healthcare utilisation,54 hospitalisation (3 years),18 mortality18 | Functional decline18 |
| C=Weighted indices | ||
| ACE | Healthcare expenditure23 | |
| Cambridge MM Score | Mortality,97 primary care consultation,97 unplanned admission97 | |
| CCI | Ambulatory care-sensitive hospitalisations (acute and chronic),106 disability,17 emergency department visits (1 year),21 emergency hospital admission (2 years),119 frailty,17 functional decline (2 years),119 future physical functioning,28 healthcare expenditure,21 hip fractures,103 hospitalisation (1 year),21 64 80 99 109 hospitalisation (3 years),18 mortality (1 year),50 63 99 109 mortality (3 years),18 (5 years),51 63 (10 years),51 63 (15, 20, 25 years),51 number of primary care consultations (3 years),48 number of primary care physician visits (1 year),107 number of specialist visits (1 year),107 potentially preventable unplanned admission (1 year),96 presence of critical illness,46 primary healthcare cost,47 mortality (1 year),57 58 (3 years),48 59 (5 years),58 60 62 (7 years),86 (10 years),28 readmission within 30 days (1 year),21 successful ageing61 | Functional decline,18 primary care visits,69 quality of cardiovascular preventive care,27 quality of preventive care27 |
| CLS | Mortality (1 year)57 | |
| DBIS | Quality of life98 | |
| EI (original and modified) | Hospitalisation (1 year),99 109 mortality (1 year)57 99 109 | |
| ERA | Healthcare expenditure,21 mortality (2 years),113 number of days hospitalised (1 year),56 number of emergency department visits (1 year),21 56 number of hospital admissions (1 year),21 56 number of hospital visits (1 year),21 56 nursing home placement (2 years),113 presence of critical illness,46 readmission within 30 days (1 year)21 | |
| HCC | Hospitalisation (1 year),21 ED visits (1 year),21 readmission within 30 days (1 year),21 healthcare expenditure (1 year)21 | |
| M3 Index | Hospitalisation (1 year),109 mortality (1 year)109 | |
| MDMS | Sickness absence episodes taken in 2 years (male)24 | Sickness absence episodes taken in 2 years (female)24 |
| MM weighted by ADL scale | Life satisfaction,22 perceived health status22 | |
| MM weighted by HUI | Life satisfaction,22 perceived health status22 | |
| MM weighted by HUI betas | Life satisfaction,22 perceived health status22 | |
| MWI | ADL limitations,121 IADL limitations,121 mortality (10 years),28 cognitive performance,121 future physical functioning,28 125 grip strength,121 health-related quality of life,123 mortality,125 subjective physical functioning,121 suicide mortality123 | Gait speed28 |
| QOF (standard) | Mortality (1 year)50 | |
| QOF (extended) | Mortality (1 year)50 | |
| Severity Burden Score | Mental component score (SF-12)94 | |
| D=Other approaches (D-1=Case Mix, D2=Pharmaceutical-based) | ||
| ACG | Hospitalisation (1 year),80 mortality (3 years),48 number of primary care consultations (3 years),48 primary healthcare cost,47 readmission within 30 days (1 year)21 | |
| ADG | Hospitalisation (1 year),107 number of primary care physician visits (1 year),107 number of specialist visits (1 year)107 | |
| CRG | Healthcare expenditure,49 HRQoL using EQ-5D-3L87 | |
| Adjusted Morbidity Groups (GMA) | Use of healthcare resources88 | |
| HM | Emergency department visits (1 year),21 healthcare expenditure,21 hospitalisation (1 year),21 readmission within 30 days (1 year)21 | |
| HSMI | Healthcare cost (primary care)78 | |
| Minnesota Tiering | Emergency department visits (1 year),21 114 healthcare expenditure,21 hospitalisation (1 year),21 114 readmission within 30 days (1 year)21 | |
| Resource Utilisation Band | Fee-for-service expenditures,77 primary healthcare cost,47 mortality (3 years),48 number of primary care consultations (3 years),48 registered active listing in primary care,100 registered active listing in all healthcare100 | |
| CDS | Hospitalisation (1 year),99 mortality (1 year)99 | |
| Drug Count | Emergency hospital admission (2 years),120 functional decline (2 years),120 hospitalisation (1 year),99 mortality (1 year),99 (3 years),48 number of primary care consultations (3 years)48 | |
| Pra tool Modified using RxRisk-V | Emergency hospital admission (1 year)119 | |
| RxRisk-V | Emergency hospital admission (2 years),120 functional decline (2 years)120 | |
ACE-27, Adult Comorbidity Evaluation; ACG, Adjusted Clinical Groups; ADG, Aggregated Diagnosis Groups; ADL, Activities of Daily Living; CCC, Chronic Condition Count; CCI, Charlson Comorbidity Index; CDC, Chronic Disease Count; CDS, Chronic Disease Score; CIRS, Cumulative Illness Rating Scale; CLS, Comorbidity Linked Score; CRG, Clinical Risk Groups; DBIS, Disease Burden Impact Scale; DC, Disease Count; EI, Elixhauser Index; ERA, Elder Risk Assessment; HCC, Hierarchical Condition Categories; HM, Hybrid Model (MN Tier+ERA); HRQoL, health-related quality of life; HSMI, Health Search Morbidity Index; HUI, Health Utility Index; MDMS, Multidimensional Multimorbidity Score; M3 Index, Multimorbidity Measure (M3) Index; MM, Multimorbidity; MWI, Multimorbidity-Weighted Index; Pra tool, Probability of repeated admission risk prediction tool; QOF, Quality and Outcomes Framework; RxRisk-V, A Veterans Association adapted pharmacy-based case-mix instrument; SF-12, Short Form-12.