Table 3.
Associations of Albuminuria with Incident Chronic Lower Respiratory Disease Events during a Median of 15 Years of Follow-up (NHLBI Pooled Cohorts Study)
| At Risk | Events (Cumulative Incidence) | Albuminuria Categories |
ln Albuminuria |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| <2 mg/dl (n = 1,568) | 2–3 mg/dl (n = 1,610) | 3–6 mg/dl (n = 4,293) | 6–12 mg/dl (n = 3,091) | 12–30 mg/dl (n = 2,016) | ≥30 mg/dl (n = 1,635) | Per SD (95% CI) (n = 14,213) | P Value | |||
| CLRD events | ||||||||||
| Severe CLRD event | 14,213 | 379 (2.67) | Ref. | 1.09 | 1.07 | 0.98 | 1.34 | 1.52 | 1.17 (1.04–1.30) | 0.0074 |
| CLRD-related event | 14,069 | 1,414 (10.05) | Ref. | 0.97 | 1.07 | 1.00 | 1.25* | 1.76* | 1.23 (1.16–1.30) | <0.0001 |
| COPD events | ||||||||||
| Severe COPD event | 14,213 | 298 (2.10) | Ref. | 1.22 | 1.18 | 1.14 | 1.66 | 1.87* | 1.23 (1.08–1.39) | 0.0013 |
| COPD-related event | 14,069 | 1,114 (7.92) | Ref. | 1.00 | 1.10 | 1.10 | 1.34* | 1.93* | 1.26 (1.18–1.34) | <0.0001 |
| Asthma events | ||||||||||
| Severe asthma event | 14,213 | 84 (0.59) | Ref. | 0.68 | 0.86 | 0.62 | 0.73 | 0.93 | 1.04 (0.81–1.35) | 0.75 |
| Asthma-related event | 14,069 | 319 (2.27) | Ref. | 0.95 | 0.98 | 0.71 | 1.02 | 1.21 | 1.07 (0.94–1.22) | 0.29 |
Definition of abbreviations: CI = confidence interval; CLRD = chronic lower respiratory disease; COPD = chronic obstructive pulmonary disease; Ref. = reference.
Results exclude participants with prevalent CLRD at time of albuminuria measurement. CLRD-related events were defined as hospitalizations or deaths adjudicated as primarily or secondarily attributable to CLRD or, when adjudication was lacking, those with CLRD listed in any diagnosis field. Severe CLRD events were defined as hospitalizations or deaths adjudicated as primarily attributable to CLRD or, when adjudication was lacking, with CLRD coded as the primary discharge diagnosis or underlying cause of death. COPD and asthma events are subsets of CLRD events; there was coincidence of COPD and asthma events in certain participants. Cox proportional hazards models were used. The time to event was treated as age at event, with left truncation at age at albuminuria measurement. Non-CLRD mortality was censored. The study was treated as a stratum term, allowing for cohort-specific differences in the underlying survival function. Models were adjusted for baseline age, birth year, height, weight, sex, race/ethnicity, educational attainment, smoking status, pack-years of smoking, hypertension status, hypertension medications, systolic blood pressure, diastolic blood pressure, total cholesterol, angiotensin-converting enzyme inhibitor/angiotensin-II receptor blocker medication, diabetes status, diabetes medication, and estimated glomerular filtration rate. Separate models were run using categorical (grouped quantile) and continuous (natural log–transformed albuminuria) predictors, and effect estimates were reported per category or per SD, respectively. Model fit was compared by the Akaike information criterion (AIC). For all endpoints, the AIC for the categorical analysis was higher (worse) than for the continuous term (COPD/primary cause, 3,910.37 vs. 3,903.88; COPD/contributing cause, 14,978.94 vs. 14,967.12; asthma/primary cause, 1,170.38 vs. 1,164.38; asthma/contributing cause, 4,519.81 vs. 4,517.58).
P < 0.05.