Table 1.
Multimorbidity Characteristics of Participants at Baseline, Nurses’ Health Study (2000), Health Professionals Follow-Up Study (2000), and Nurses’ Health Study II (2001)
| Participant Characteristic | Nurses’ Health Study (n = 92,352) |
Health Professionals Follow-Up Study (n = 32,476) |
Nurses’ Health Study II (n = 95,122) |
Meta-Analyzed Combined Cohorts (n = 219,950) |
|||
|---|---|---|---|---|---|---|---|
| Mean (SD) | IQR | Mean (SD) | IQR | Mean (SD) | IQR | Mean (SD) | |
| Age, years | 66.03 (7.1) | 66.62 (9.2) | 46.42 (5.0) | 57.60 (3.7) | |||
| MWI | 4.46 (4.3) | 4.36 (4.0) | 2.93 (3.3) | 3.76 (2.2) | |||
| MWI quartile | |||||||
| 4 | 6.43–48.00 | 6.10–50.80 | 4.27–35.10 | ||||
| 3 | 3.54–6.42 | 3.16–6.09 | 1.80–4.26 | ||||
| 2 | 1.20–3.53 | 1.52–3.15 | 0.34–1.79 | ||||
| 1 | <1.20 | <1.52 | <0.34 | ||||
| Disease count | 3.31 (2.4) | 2.93 (2.3) | 2.19 (1.9) | 2.71 (1.2) | |||
| Disease count quartile | |||||||
| 4 | 5.00–2300 | 4.00–19.00 | 3.00–18.00 | ||||
| 3 | 3.00–4.99 | 2.00–3.99 | 2.00–2.99 | ||||
| 2 | 2.00–2.99 | 1.00–1.99 | 1.00–1.99 | ||||
| 1 | <2.00 | <1.00 | <1.00 | ||||
| CCI | 0.54 (1.0) | 0.54 (1.0) | 0.20 (0.6) | 0.43 (0.6) | |||
| CCI quartile | |||||||
| 4 | 1.00–13.00 | 1.00–12.00 | N/Aa | ||||
| 3 | 0.00–0.99 | 0.00–0.99 | |||||
| 2 | 0 | 0 | |||||
| 1 | 0 | 0 | |||||
Abbreviations: CCI, Charlson Comorbidity Index; IQR, interquartile range; MWI, multimorbidity-weighted index; N/A, not calculable in quartiles; SD, standard deviation.
a In the Nurses’ Health Study II, the CCI was not computable in quartiles because of a strong left skew. Decile 10 corresponds to a CCI of 1–7; decile 9 corresponds to a CCI of 0–1; and deciles 1–8 correspond to a CCI of 0.