Table 1.

Summary of the relationship between multimorbidity, costs, and utilisationa

Utilisation/cost typeMM specificationMagnitude (95% CI)Parameter estimate typeReference
Primary care visits (n = 3)
Number of QOF LTCs Embedded Image0.37 (0.36 to 0.38)Marginal effect28
MM vs not Embedded Image2.56 (2.48 to 2.64)Odds ratio3
Dental visits (n = 1)
MM vs not Embedded Image1.23 (1.08 to 1.38)Odds ratio36
A&E visits (n = 2)
HADS score of 8 or more vs lower Embedded Image1.58 (1.04 to 2.41)Odds ratio35
1 QOF LTC vs none Embedded Image1.12 (1.10 to 1.13)Odds ratio24
2 QOF LTC vs none Embedded Image1.28 (1.25 to 1.31)Odds ratio24
3 QOF LTC vs none Embedded Image1.65 (1.59 to 1.71)Odds ratio24
≥4 QOF LTC vs none Embedded Image2.55 (2.44 to 2.66)Odds ratio24
Hospitalisations (n = 4)
All1 LTC vs none Embedded Image1.77 (1.59 to 1.98)Odds ratio33
2 LTC vs none Embedded Image2.41 (2.12 to 2.72)Odds ratio33
3 LTC vs none Embedded Image3.53 (3.06 to 4.07)Odds ratio33
≥4 QOF LTC vs none Embedded Image4.33 (3.63 to 5.17)Odds ratio33
MM vs not Embedded Image2.58 (2.48 to 2.69)Yearly rate ratio3
Unplanned all1 PC vs none Embedded Image1.70 (1.59 to 1.82)Odds ratio27
2 PC vs none Embedded Image2.69 (2.50 to 2.89)Odds ratio27
3 PC vs none Embedded Image3.47 (3.21 to 3.76)Odds ratio27
≥4 PC vs none Embedded Image5.87 (5.45 to 6.32)Odds ratio27
Unplanned potentially preventable1 PC vs none Embedded Image2.50 (2.07 to 3.03)Odds ratio27
2 PC vs none Embedded Image4.93 (4.06 to 5.99)Odds ratio27
3 PC vs none Embedded Image6.82 (5.55 to 8.37)Odds ratio27
≥4 PC vs none Embedded Image14.38 (11.87 to 17.43)Odds ratio27
Prolonged length of stayMM vs not (90+ population) Embedded Image0.61 (0.32 to 1.13)Risk ratio23
Total costs (n = 3)
1–3 LTC vs none Embedded Image1.62 (1.28 to 2.03)Mean ratio31
4–6 LTC vs none Embedded Image2.53 (2.01 to 3.19)Mean ratio31
7–9 LTC vs none Embedded Image3.82 (3.01 to 4.85)Mean ratio31
1 LTC vs none Embedded Image1.99 (1.95 to 2.03)Mean ratio26
2 LTC vs none Embedded Image2.53 (2.46 to 2.58)Mean ratio26
3 LTC vs none Embedded Image2.86 (2.72 to 3.03)Mean ratio26
Care transition costs (n = 1)Comorbidity pairs vs index LTC Embedded ImageP<0.001Increasing trend in association34
Primary care costs (n = 2)Costs of 1 patient with 2 Embedded ImageIncreasing or decreasing costs when co-occurringEstimated prevalence- adjusted cost13
LTC vs 2 separate
patients with each LTC
Hospital costs (n = 1)Individual LTC Embedded ImageP<0.01 for 90% of the estimated coefficientsEstimated coefficient25
Time to death as a proxy for morbidity
  • a The number of articles is indicated in parentheses next to the cost or utilisation type (see Supplementary Appendix S3 for the complete 17 study references). Mean ratios can be obtained by exponentiating the parameter estimates from a generalised linear model with the log-link; they have an interpretation similar to an odds ratio. For example, individuals with 7–9 conditions have 3.82 times the mean expected total costs of individuals without comorbidities. A&E = accident and emergency. CI = confidence interval. HADS = Hospital Anxiety and Depression Scale. LTC = long-term condition. MM = multimorbidity. PC = physical condition. QOF = Quality and Outcomes Framework. Prolonged length of stay is defined as 7 days in the hospital. Care transitions are defined as healthcare changes from general practice to emergency department or hospital care.