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Volume 32, Number 6—June 2026
Research
Association of Frailty and Frailty Trajectory with Risk for Respiratory Infectious Diseases
Table 3
Hazard ratios of incident RIDs in final assessment of association of frailty and frailty trajectory with risk for RIDs*
| Category | Events/no. participants | Model 1 |
Model 2 |
|||
|---|---|---|---|---|---|---|
| HR (95% CI) | p value | HR (95% CI) | p value | |||
| Grouped by physical frailty | ||||||
| Nonfrail | 462/8,089 | Referent | Referent | |||
| Prefrail | 655/8,350 | 1.28 (1.14–1.45) | <0.001 | 1.17 (1.04–1.33) | 0.011 | |
| Frail | 72/409 | 3.04 (2.37–3.90) | <0.001 | 2.27 (1.75–2.95) | <0.001 | |
| Per 1-point increase |
1.36 (1.27–1.46) |
<0.001 |
1.25 (1.17–1.35) |
<0.001 |
||
| Grouped by frailty index | ||||||
| Nonfrail | 573/10,424 | Referent | Referent | |||
| Prefrail | 495/5,794 | 1.44 (1.27–1.62) | <0.001 | 1.28 (1.13–1.45) | <0.001 | |
| Frail | 121/630 | 3.31 (2.72–4.03) | <0.001 | 2.59 (2.10–3.19) | <0.001 | |
| Per 0.1-point increase |
1.66 (1.53–1.80) |
<0.001 |
1.48 (1.36–1.62) |
<0.001 |
||
| RID subgroups | ||||||
| Influenza | ||||||
| Grouped by physical frailty | ||||||
| Nonfrail | 9/8,089 | Referent | Referent | |||
| Prefrail | 20/8,350 | 2.04 (0.92–4.50) | 0.078 | 1.81 (0.81–4.05) | 0.146 | |
| Frail | 2/409 | 4.04 (0.87–18.81) | 0.075 | 2.36 (0.45–12.47) | 0.312 | |
| Per 1-point increase |
1.38 (0.96–1.98) |
0.079 |
1.20 (0.79–1.80) |
0.382 |
||
| Grouped by frailty index | ||||||
| Nonfrail | 18/10,424 | Referent | Referent | |||
| Prefrail | 9/5,794 | 0.85 (0.38–1.91) | 0.696 | 0.73 (0.32–1.65) | 0.443 | |
| Frail | 4/630 | 3.35 (1.12–9.98) | <0.05 | 2.09 (0.63–6.95) | 0.228 | |
| Per 0.1-point increase | 1.82 (1.15–2.90) | <0.05 | 1.53 (0.94–2.50) | 0.087 | ||
| OALRTI | ||||||
| Grouped by physical frailty | ||||||
| Nonfrail | 242/8,089 | Referent | Referent | |||
| Prefrail | 301/8,350 | 1.12 (0.94–1.33) | 0.194 | 1.03 (0.86–1.22) | 0.760 | |
| Frail | 28/409 | 2.13 (1.44–3.16) | <0.001 | 1.64 (1.09–2.48) | <0.05 | |
| Per 1-point increase | 1.22 (1.10–1.36) | <0.001 | 1.14 (1.02–1.27) | 0.024 | ||
| Grouped by frailty index | ||||||
| Nonfrail | 278/10,424 | Referent | Referent | |||
| Prefrail | 233/5,794 | 1.40 (1.18–1.67) | <0.001 | 1.28 (1.07–1.53) | 0.007 | |
| Frail | 60/630 | 3.29 (2.49–4.36) | <0.001 | 2.77 (2.06–3.73) | <0.001 | |
| Per 0.1-point increase | 1.63 (1.45–1.83) | <0.001 | 1.51 (1.32–1.71) | <0.001 | ||
| Pneumonia | ||||||
| Grouped by physical frailty | ||||||
| Nonfrail | 247/8,089 | Referent | Referent | |||
| Prefrail | 408/8,350 | 1.47 (1.26–1.73) | <0.001 | 1.34 (1.14–1.58) | <0.001 | |
| Frail | 53/409 | 4.12 (3.06–5.55) | <0.001 | 2.96 (2.16–4.05) | <0.001 | |
| Per 1-point increase | 1.53 (1.40–1.67) | <0.001 | 1.39 (1.27–1.52) | <0.001 | ||
| Grouped by frailty index | ||||||
| Nonfrail | 320/10,424 | Referent | Referent | |||
| Prefrail | 312/5,794 | 1.58 (1.35–1.84) | <0.001 | 1.38 (1.17–1.62) | <0.001 | |
| Frail | 76/630 | 3.53 (2.75–4.55) | <0.001 | 2.67 (2.04–3.50) | <0.001 | |
| Per 0.1-point increase | 1.73 (1.56–1.92) | <0.001 | 1.52 (1.35–1.70) | <0.001 | ||
*Data from UK Biobank (https://www.ukbiobank.ac.uk) collected during 2012–2013. Model 1 is adjusted for age and sex; model 2 is adjusted for all covariates. HRs and 95% CIs were estimated using Cox proportional hazards models. A 2-sided p<0.05 was considered statistically significant. FI, frailty index; HR, hazard ratio; OALRTI, other acute lower respiratory tract infection; PF, physical frailty; RID, respiratory infectious disease.
1These first authors contributed equally to this article.