Table 1.
Characteristics of pneumonia cases and controls
| Pneumonia cases (N=1,039) |
Controls (N=2,022) |
|
|---|---|---|
| Characteristic* | n (%)† | n (%)† |
| Median age (IQR), years‡ | 77 (71 – 82) | 77 (71 – 82) |
| Male‡ | 525 (50.5) | 1030 (50.9) |
| Case validated from: | ||
| Radiograph report | 963 (85.6) | NA |
| Other medical records | 126 (11.2) | NA |
| Valid by default§ | 36 (3.2) | NA |
| Median BMI (IQR), kg/m2† | 26.5 (23.4 – 30.6) (N=736) |
27.3 (24.5 – 30.6) (N=1341) |
| Median weight (IQR), kg | 74.5 (62.7 – 86.8) | 76.4 (65.0 – 87.7) |
| Median height (IQR), cm† | 168 (160 – 175) (N=737) |
168 (160 – 175) (N=1347) |
| Current smoker | 94/1027 (9.2) | 101/1972 (5.1) |
| Asthma | 185 (17.8) | 158 (7.8) |
| Chronic obstructive pulmonary disease (COPD) |
324 (31.2) | 227 (10.4) |
| Hospitalized for COPD | 50 (4.8) | 14 (0.7) |
| Home oxygen use | 83 (8.0) | 18 (0.9) |
| Long term oral corticosteroid use for lung disease |
28 (2.7) | 6 (0.3) |
| FEV1 measured | 166 (16.0) | 78 (3.9) |
| Congestive heart failure (CHF) | 192 (18.5) | 141 (7.0) |
| Hospitalized for CHF | 33 (3.2) | 16 (0.8) |
| Ejection fraction measured | 72 (6.9) | 35 (1.7) |
| Myocardial infarction | 126 (12.1) | 199 (9.8) |
| Coronary revascularization | 145 (14.0) | 224 (11.1) |
| Other heart conditions | 411 (39.6) | 640 (31.7) |
| Hypertension | 479 (46.1) | 949 (46.9) |
| Stroke | 87 (8.4) | 140 (6.9) |
| Swallowing disorder leading to aspiration | 13 (1.3) | 9 (0.4) |
| Alcoholism | 16 (1.5) | 22 (1.1) |
| Diabetes mellitus | 172 (16.6) | 300 (14.8) |
| Diabetes mellitus with complications | 97 (9.3) | 163 (8.1) |
| Dementia | 48 (4.6) | 68 (3.4) |
| At least one functional impairment | 191 (18.4) | 232 (11.5) |
| Requires assistance bathing | 22 (2.1) | 15 (0.7) |
| Requires assistance walking | 184 (17.7) | 221 (10.9) |
| Any use of home health services | 150 (14.4) | 125 (6.2) |
| Frail║ | 84 (8.1) | 58 (2.9) |
| Bronchodilator use¶ | 138 (13.3) | 51 (2.5) |
| Furosemide use¶ | 231 (22.2) | 206 (10.2) |
| Inhaled corticosteroid use¶ | 244 (23.5) | 159 (7.9) |
| Insulin or oral hypoglycemic use¶ | 114 (11.0) | 188 (9.3) |
| Oral corticosteroid use¶ | 262 (25.2) | 191 (9.4) |
| Received pneumococcal vaccine** | 951 (91.5) | 1846 (91.3) |
| Received influenza vaccine†† | 630 (60.6) | 1245 (61.6) |
| Number of outpatient visits, median (IQR)‡‡ | 11 (6 – 17) | 8 (5 – 14) |
Abbreviations: BMI, body mass index; IQR, interquartile range; FEV1, forced expiratory volume in 1 second; GH, Group Health.
All characteristics are defined as of September 1 and are defined for the 2 year baseline period unless otherwise stated. Except as stated below, all covariates were measured by manual review of medical records.
Results are provided as n (%) unless otherwise stated. Less than 5% of people had missing values for all characteristics except for BMI, which was missing for 29% of cases and 34% of controls, and height, missing for 29% of cases and 33% of controls.
Matching variable used in selection of controls.
Cases were considered valid by default if they were diagnosed with pneumonia at an outside emergency department and no GH radiograph report was available; see Methods.
Ever described as frail by medical personnel (from chart review).
Defined from computerized pharmacy data as filling at least one prescription during the 2 year baseline period.
Any history of receiving pneumococcal vaccine.
Receipt of the current year’s influenza vaccine prior to index date.
Number of visits in 1-year baseline, from GH automated utilization data.