Table 4.
Secondary analysis: Hazard ratios for incident clinically significant dyspnea on exertion (MRC score ≥ 3) by sociodemographic, lifestyle, clinical, and RA characteristics among subjects with no dyspnea (MRC score = 0) at baseline (n = 736, number of outcomes = 86)
| Time‐updated predictor | Unadjusted HR (95% CI) | Sociodemographics model HR (95% CI) | Lifestyle and clinical model HR (95% CI) | RA characteristics model HR (95% CI) | Final multivariable HR (95% CI) |
|---|---|---|---|---|---|
| Sociodemographics | |||||
| Age (per year) | 1.03 (1.01‐1.05) | 1.04 (1.02‐1.06) | 1.03 (1.01‐1.05) | 1.03 (1.01‐1.06) | 1.03 (1.00‐1.05) |
| Female sex (vs male) | 1.78 (0.88‐3.59) | 2.21 (1.08‐4.53) | 2.46 (1.19‐5.09) | 2.14 (1.03‐4.45) | 2.03 (0.98‐4.20) |
| White race (vs nonwhite) | 0.55 (0.27‐1.13) | 0.49 (0.23‐1.00) | – | – | – |
| College degree (vs less education) | 0.67 (0.43‐1.03) | 0.85 (0.54‐1.33) | – | – | – |
| Lifestyle and clinical | |||||
| Body mass index category | – | – | – | ||
| Underweight/normal | 1.00 (Ref) | 1.00 (Ref) | |||
| Overweight | 1.73 (1.03‐2.89) | 1.53 (0.90‐2.61) | |||
| Obesity | 2.36 (1.36‐4.07) | 2.21 (1.24‐3.92) | |||
| Smoking status | – | – | |||
| Never | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | ||
| Past | 1.76 (1.12‐2.75) | 1.38 (0.87‐2.18) | 1.48 (0.94‐2.35) | ||
| Current | 1.38 (0.53‐3.59) | 1.15 (0.43‐3.05) | 1.13 (0.42‐3.00) | ||
| Physical activity (per MET‐hour/week) | 0.95 (0.90‐0.99) | – | 0.98 (0.93‐1.02) | – | – |
| Pulmonary morbidity (vs none)a | 1.95 (1.16‐3.28) | – | 1.51 (0.88‐2.61) | – | 1.46 (0.85‐2.53) |
| Multimorbidity index count | – | – | |||
| 0 | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | ||
| 1 | 1.62 (0.93‐2.83) | 1.46 (0.83‐2.58) | 1.38 (0.78‐2.44) | ||
| >1 | 2.21 (1.30‐3.76) | 1.60 (0.92‐2.80) | 1.55 (0.88‐2.71) | ||
| Cough (vs none) | 1.57 (0.98‐2.51) | – | 1.18 (0.72‐1.94) | – | 1.27 (0.78‐2.08) |
| Anxiety (vs none) | 1.66 (1.07‐2.57) | 1.57 (1.00‐2.46) | 1.16 (0.72‐1.85) | ||
| RA characteristics | |||||
| DAS28‐CRP3 continuous (per unit) | 1.13 (0.98‐1.30) | – | – | – | – |
| Moderate/high DAS28‐CRP (vs low/remission) | 1.44 (0.93‐2.23) | – | – | 0.94 (0.57‐1.53) | 0.96 (0.59‐1.54) |
| RA duration (per year) | 1.02 (0.99‐1.03) | – | – | 1.00 (0.97‐1.02) | – |
| Seropositive (vs seronegative) | 0.99 (0.61‐1.59) | – | – | 0.83 (0.48‐1.44) | – |
| MDHAQ (per unit) | 3.08 (2.07‐4.57) | – | – | 2.73 (1.72‐4.32) | 2.48 (1.56‐3.94) |
| Methotrexate use (vs not) | 0.77 (0.50‐1.19) | – | – | 0.66 (0.37‐1.16) | – |
| Non‐biologic DMARD use (vs not) | 0.88 (0.54‐1.41) | – | – | 1.30 (0.68‐2.48) | – |
| Biologic DMARD use (vs not) | 1.38 (0.89‐2.14) | – | – | 1.63 (1.01‐2.63) | – |
| Glucocorticoid use (vs not) | 1.70 (1.07‐2.68) | – | – | 1.11 (0.72‐1.71) | – |
| Erosion present (vs not) | 0.99 (0.64‐1.52) | – | – | 0.64 (0.37‐1.08) | – |
| Rheumatoid nodule present (vs not) | 1.73 (1.11‐2.70) | – | – | 1.63 (0.95‐2.80) | – |
a
Pulmonary morbidities were asthma, bronchitis, emphysema, pneumonia, or interstitial lung disease. Bold values indicate P < 0.05.
CI = confidence interval; DAS28‐CRP3 = disease activity score with 28 joints and C‐reactive protein; DMARD = disease‐modifying antirheumatic drug; HR = hazard ration; MDHAQ = multi‐dimensional health assessment questionnaire; MET‐hours/week = metabolic equivalent of tast in hours per week; MRC = Medical Research Council; RA = rheumatoid arthritis.