Table 2.
Author Publication Year Country |
Population and setting | Definition and prevalence of multimorbidity (MM) | Functional decline outcome measure/s | Follow-up period Losses to follow-up (%) |
Results |
---|---|---|---|---|---|
Abizanda 2014 Spain |
General population (FRADEA Study) 842 adults aged >70 yrs |
MM ≥2 chronic diseases in a specific period of time. 14 pre-specified conditions selected for prevalence and impact on disability/mortality Chronic diseases identified from medical records and coded via ICD-10 580 ≥ 2 conditions (69.0 %) |
Barthel index (disability) Fried’s criteria (frailty) |
2 years 7.5 % loss to follow-up |
Disability and frailty was not associated with MM over two years. |
Aarts 2012 Netherlands |
Primary care (Maastricht Aging Study) 1184 adults aged 21–84 years |
MM ≥2 chronic diseases co-occurring within one person Morbidities sourced from GP database including all current and past health problems by clinician 96 included conditions based on medical literature and clinical experience 35.5 % ≥ 2 chronic diseases |
SF-36 | 3 and 6 years 16.4 % loss to follow-up |
MM significantly associated with poorer physical functioning at all 3 follow-up points (p < 0.001) Significant steep decline in physical function between 3 and 6 year follow up in those with MM (p < 0.001) Participants whose morbidity status changed from baseline to 3 year follow up (either to single or MM) associated with significantly lower physical function (p < 0.001) |
Bayliss 2004 USA |
Primary care (Medical Outcomes Study) 2708 adults, mean age 57.6 years |
No definition of MM reported Self-report of 7 pre-specified chronic conditions. Condition presence also sourced from records Conditions chosen as of high prevalence in practice and in literature 686 ≥ 2 chronic diseases (25.3 %) |
SF-36 (PCS scores) |
4 years 41.9 % loss to follow up |
≥4 chronic diseases associated with significant decline in physical function (p < 0.05) Reduction in PCS by 6.5 used as criteria for clinically significant <4 chronic diseases no association with physical decline Congestive Heart Failure, diabetes and/or respiratory disease predictive of clinically significant decline in PCS (p <0.05) |
Byles 2005 Australia |
Primary care (Veteran’s Affairs Preventative Care Trial) 1417 adults ≥70 years |
Co-existence of multiple diseases in the same individual Self-reported MM questionnaire consisting of 25 conditions Severity measure incorporated and included mild cognitive decline 1107 > 3 conditions (78.1 %) |
SF-36 | 2 years 7.2 % lost to follow up |
Quality of Life (QoL) decreases as number of conditions increases The presence of each condition associated with significantly lower SF-36 scores (except heart bypass, stroke and diabetes) Data not shown |
Drewes 2011 Netherlands |
General population (Leiden 85–plus study) 594 adults aged 85 years |
MM ≥2 chronic diseases at age 85 years Chart confirmed presence of 9 common conditions pre-specified 234 ≥ 2 chronic diseases (39.4 %) |
Groningen Activity Restriction Scale | 5 years 53.9 % loss to follow up |
Participants with MM had an accelerated progression of ADL (activities of daily living) disability over time compared to those without MM (95 % CI 0.21 -0.63, p < 0.001) MM demonstrated accelerated increase in ADL disability in older people with optimal cognitive function (95 % CI 0.39-0.95, p < 0.001) This was not observed in participants with lower MMSE scores. |
Kiely 1997 USA |
Community based (Sample first drawn 1982: Massachusetts state-supported home care programme) 1060 adults aged ≥65 years |
No definition of MM reported Self-report of 5 pre-specified medical conditions MM numbers not reported |
Functional Dependency Index (FDI) |
3 years 22.5 % loss to follow up |
Each additional medical condition resulted in a significant increase in the FDI score (p < 0.001) Rate of decline did not differ by total number of medical conditions (p =0.67) |
Nikolova 2011 Canada |
Community based (Research Program on Integrated Services for the Elderly) 1164 disabled adults ≥65 years Disability status estimated using the Functional Autonomy Measurement System (SMAF) Score ≥10 excluded |
Comorbidity : number of chronic diseases Self-report of comorbidities using 16 item questionnaire Diseases not specified but grouped into four categories: 0-1 disease 2-3 diseases 4-5 diseases ≥6 diseases 1084 ≥ 2 diseases (93.1 %) |
Functional status measured using 7 item IADL subscale of the OAR and Katz ADL index | 3 years High rate of attrition discussed but loss to follow up number NR |
Comorbidity burden is a strong predictor in developing IADL and ADL disability 6 diseases vs 0–1 disease OR (95 % CI) IADL 6.42 (1.52; 27.18) ADL 16.73 (3.08; 91.06) 4 –5 diseases vs 0–1 disease OR(95 % CI) IADL 1.20 (0.52; 2.80) ADL 0.89 (0.26; 2.98) 2–3 diseases vs 0 –1 disease OR(95 % CI) IADL 1.00 (0.46; 2.20) ADL 1.44 (0.49; 4.15) ≥6 morbidities-6 times more likely to develop ADL disability and 17 times more likely to develop IADL disability |
Prior 2011 UK |
Primary care 4672 adults aged ≥50 years |
Comorbidity –number of chronic diseases Record confirmed condition counts over previous 2 years In addition to number of GP consultations for morbidity in 2 year period Specific cardiovascular and musculoskeletal conditions (n = 15) chosen as most prevalent in developed countries Stage of disease as proxy for severity 561 ≥ 1 CVD & MSK condition MM in overall group not reported |
SF-12 (PCS) | 3 years 46 % loss to follow up |
Cardiovascular cohort: higher comorbidity and increasing severity in disease associated with greater deterioration in PCS. Significant deterioration shown for HTN (p < 0.001) with PCS score deteriorating by -0.86 over three years Musculoskeletal cohort: no association |
Rigler 2002 USA |
Community based (Veteran’s Affairs Medical Centre) 492 adults aged ≥65 years |
Comorbidity scores: based on sum of the domains affected, and the sum of the domains which patients reported affected function. Self-report of 18 prevalent conditions from 8 organ domains via self-report 335 ≥ 2 diagnoses (68.1 %) |
MOS-36 Physical Function Index Self-report ADL and IADL |
1 year 7.2 % loss to follow up |
Increasing comorbidity significantly associated with increased risk of future functional decline (p <0.001) OR 1.09: 2 conditions OR 2.41: ≥ 3 conditions Presence of ADL and IADL problems at baseline demonstrated to have a significant impact on new ADL problems developing at one year (p <0.001) OR 4.77: 1 IADL problem at baseline OR 15.6: 1 ADL problem at baseline |