Decreased Risk of COPD Exacerbations in Obese Patients

Figures & data

Table 1. Baseline characteristics of patients admitted with a clinical exacerbation of chronic obstructive lung disease (COPD).

	All	Underweight	Normal weight	Overweight	Moderately obese	Severely obese
BMI (kg/m^2)		<18.5	18.5–<25	25–<30	30–<35	≥35
	n = 604	n = 71	n = 266	n = 155	n = 71	n = 41
Sex (male)	281 (47%)	31 (44%)	126 (47%)	79 (51%)	33 (47%)	12 (29%) p = 0.042
Age (years)	68 ± 11	66 ± 13 p = 0.010	69 ± 12	69 ± 11	67 ± 11	66 ± 9
Active smoking	268 (48%)	41 (59%)	118 (48%)	60 (43%)	32 (50%)	17 (50%)
Pack-years (years)	42 ± 28	41 ± 47	40 ± 23	44 ± 22	48 ± 30	37 ± 35
Gold stage I	27 (5%)	1 (1%)	9 (3%)	8 (5%)	5 (7%)	4 (10%) p = 0.081
Gold stage II	153 (25%)	10 (14%)	64 (24%)	41 (27%)	24 (34%) p = 0.095	14 (34%)
Gold stage III	242 (40%)	28 (39%)	110 (41%)	61 (39%)	26 (37%)	17 (42%)
Gold stage IV	180 (30%)	32 (47%) p = 0.024	82 (31%)	44 (28%)	16 (23%)	6 (15%) p = 0.040
FEV1 (L)	1.24 ± 4.05	0,87 ± 0.31	1.04 ± 0.48	1.81 ± 8.11	1.21 ± 0.49	1.15 ± 0.50
FEV1 (% pred)	44 ± 18	35 ± 13 p = 0.001	44 ± 18	44 ± 17	49 ± 20 p = 0.046	48 ± 13
FVC (L)	2.6 ± 0.9	2.6 ± 1.0	2.6 ± 0.9	2.6 ± 0.9	2.7 ± 0.9	2.2 ± 0.9
FVC (% pred)	84 ± 22	80 ± 23	86 ± 21	82 ± 26	85 ± 18	77 ± 17
Home oxygen	84 (14%	8 (11%)	39 (15%)	26 (17%)	6 (9%)	5 (12%)
Novel COPD diagnosis	65 (11%)	11 (16%) p = 0.030	18 (7%)	24 (16%) p = 0.006	9 (13%)	3 (7%)
Asthma	47 (8%)	3 (4%)	21 (8%)	7 (5%)	9 (13%)	7 (17%)
Comorbidities (CCI)	1.20 ± 0.68	1.17 ± 0.65	1.25 ± 0.80	1.20 ± 0.68	1.15 ± 0.51	1.20 ± 0.81
Arterial blood gas: pH	7.42 ± 0.07	7.40 ± 0.09 p = 0.007	7.42 ± 0.07	7.42 ± 0.07	7.42 ± 0.07	7.40 ± 0.07 p = 0.009
Arterial blood gas: PaCO2 (kPa)	6.26 ± 2.22	6.99 ± 2.66 p = 0.001	6.16 ± 2.06	6.05 ± 2.17	6.19 ± 2.25	6.62 ± 2.36
Arterial blood gas: bicarbonate (mEq/L)	29 ± 6	30 ± 5	29 ± 5	28 ± 6	28 ± 4	29 ± 5
Hospital stay (days)	9.1 ± 6.8	8.7 ± 5.6	9.3 ± 4.4	9.4 ± 10.2	9.4 ± 6.2	9.4 ± 6.2
ICU admission	70 (12%)	8 (11%)	30 (11%)	18 (12%)	9 (13%)	5 (13%)

Values are presented as mean ± SD or number (%). BMI classes were compared to normal weight (p-values <0.05 are shown; all other p-values were not significant). BMI = Body Mass Index, CCI = Charlson comorbidities index, ICU = intensive care unit, SD = Standard Deviation.

Figure 1. Exacerbation rate. Overview per BMI class of readmissions per year over a five year period following a hospitalization for COPD exacerbation. BMI = Body Mass Index. COPD = Chronic Obstructive Lung Disease.

Figure 2. Time to readmission. Survival graph plotting percentage of patients free from readmission over a five year period following a hospitalization for an exacerbation of Chronic Obstructive Lung Disease (COPD). Patients are categorized according to Body Mass Index (BMI) class.

Figure 3. 5-year survival. Survival graph plotting survival over a five year period following a hospitalization for an exacerbation of Chronic Obstructive Lung Disease (COPD). Patients are categorized according to Body Mass Index (BMI) class.

Figure 4. Cox regression analysis of time to readmission and survival. Hazard ratios represent increased chance of readmission or death, respectively. CI=confidence interval. BMI = Body Mass Index. CCI = Charlson comorbidity index. ICU = Intensive Care Unit. NIV = non-invasive ventilation. Yrs = Years. FEV1 = Forced Expiratory Volume in 1 second. FVC = Forced Vital Capacity.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, MDK.