Impact of individualized care on readmissions after a hospitalization for acute exacerbation of COPD

Figures & data

Figure 1 Components and organization of the care package delivered by the COPD Outreach Team to patients after a hospitalization due to AECOPD.

Abbreviations: AECOPD, acute exacerbations of chronic obstructive pulmonary disease; GPs, general practitioners.

Table 1 Demographic data of subject groups with AECOPD

Variable	Pre-CP (n=271)	CP (n=191)	P-value
Age (years)	70.8 (13.8)	70.2 (12.4)	0.6134
Male (%)	64.6	58.6	0.2064
BMI (kg/m^2)	26.52 (7.65)	26.11 (7.44)	0.6313
FEV1 (% predicted)	45.65 (20.17)	47.85 (17.09)	0.3034
Number of comorbidities	3.7 (1.98)	3.8 (2.05)	0.7397
Substance abuse (%)	18.5	17.3	0.8061
Mental illness (%)	29.9	30.8	0.8376
Smoking (pack-years)	39.53 (36.16)	42.70 (31.45)	0.4087
Index admission LOS (days)	7.531 (7.301)	7.131 (7.613)	0.5687

Note: Data are presented as mean (standard deviation) or % of column totals.

Abbreviations: AECOPD, acute exacerbations of chronic obstructive pulmonary disease; CP, care package; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; LOS, length of stay.

Table 2 Demographic data of substance abuse (SA) and non-SA (NSA) groups

Variable	SA pre-CP (n=50)	SA CP (n=33)	NSA pre-CP (n=221)	NSA CP (n=158)	P-value
Age (years)	60.05 (12.44)	58.34 (8.319)	73.28 (12.09)	72.71 (11.67)	<0.0001*
Male (%)	66.00	60.60	64.25	58.23	0.6157
BMI (kg/m^2)	23.75 (6.30)	25.23 (9.04)	27.13 (7.80)	26.25 (7.17)	0.1208
FEV1 (% predicted)	41.31 (16.91)	52.60 (19.67)	46.69 (20.79)	47.03 (16.56)	0.1800
Number of comorbidities	4.26	4.42	3.62	3.67	0.0430*
Mental illness (%)	32.0	33.3	29.4	30.4	0.9609
Smoking (pack-years)	40.14 (22.29)	50.03 (28.53)	39.39 (38.70)	41.59 (31.83)	0.6506
Index admission LOS (days)	6.76 (6.413)	5.49 (4.273)	7.71 (7.490)	7.48 (8.107)	0.4009

Notes: Data are presented as mean (standard deviation) or % of column totals.

* P<0.05 difference between the SA and NSA groups.

Abbreviations: CP, care package; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; LOS, length of stay.

Figure 2 Thirty- and 90-day total, ER, and acute care readmissions in the pre-CP and CP groups.

Notes: Multivariate linear regression was used to determine significance; adjusted for covariates (age, sex, number of comorbidities, substance abuse, mental illness, and index admission length of stay).

Abbreviations: ER, emergency room; T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days; CP, care package.

Figure 3 Average time to readmission in pre-CP and CP groups.

Notes: Two-tailed Student’s t-test used to determine significance; P=0.5430.
Abbreviation: CP, care package.

Figure 4 (A) Effect of SA on readmissions. Multivariate linear regression used to determine significance; adjusted for covariates (age, sex, number of comorbidities, mental illness, care package, and index admission length of stay). (B and C) Effects of CP in SA and NSA patients, respectively. Multivariate linear regression used to determine significance in each; adjusted for covariates (age, sex, number of comorbidities, mental illness, and index admission length of stay).

Notes: *P<0.05, **P<0.01, ***P<0.001.
Abbreviations: SA, substance abuse; NSA, nonsubstance abuse; CP, care package; T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days.

Figure 5 (A) Effect of patient sex on readmissions. Multivariate linear regression used to determine significance; adjusted for covariates (age, number of comorbidities, SA, mental illness, index admission length of stay). (B and C) Effect of CP in female and male patients, respectively. Significant improvements found only in female T90 and ER90 readmissions. Multivariate linear regression used to determine significance; adjusted for covariates (age, number of comorbidities, SA, mental illness, index admission length of stay).

Notes: *P<0.05, **P<0.01.
Abbreviations: CP, care package; T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days.

Figure 6 Effect of CP on all-cause in-hospital patient mortality.

Notes: Kaplan–Meier estimate was used with a log-rank test to determine significance; P=0.0286. Hazard ratio =2.455 (95% confidence interval: 1.109–5.436).
Abbreviation: CP, care package.

Table S1 Summary of effect of CP on readmissions in whole population

Readmission	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value
	Pre-CP	CP
T30	0.4059	0.3613	0.62147	0.562
ER30	0.1956	0.1571	0.44038	0.481
AC30	0.2103	0.2042	0.9329	0.894
T90	0.9557	0.7592	0.124529	0.146
ER90	0.5055	0.3560	0.13307	0.162
AC90	0.4871	0.4031	0.26266	0.246

Notes: Summary of readmission rates in the pre-CP and CP groups. P-values are shown adjusted for covariates (age, sex, number of comorbidities, index admission length of stay, substance abuse, and mental illness) and not adjusted.

Abbreviations: T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days; CP, care package.

Table S2 Summary of effect of SA on readmissions

Readmission	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value
	SA	NSA
T30	0.7349	0.3113	0.00189	1.68e-05
ER30	0.4217	0.1266	0.0108	4.27e-06
AC30	0.3133	0.1847	0.0317	0.0847
T90	1.614	0.7124	0.000302	3.66e-08
ER90	0.9518	0.3325	0.01098	1.10e-06
AC90	0.6627	0.4063	0.0275	0.00688

Notes: Summary of readmission rates in patients with SA and without NSA comorbid substance abuse. P-values are shown adjusted for covariates (age, sex, care package, number of comorbidities, index admission length of stay, and mental illness) and not adjusted.

Abbreviations: SA, substance abuse; NSA, nonsubstance abuse; T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days.

Table S3 Summary of effect of CP on readmissions depending on presence of SA

Readmission	SA				NSA
	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value
	Pre-CP	CP			Pre-CP	CP
T30	0.7200	0.7576	0.913	0.974	0.3348	0.2785	0.4450	0.523
ER30	0.4200	0.4242	0.855	0.786782	0.1448	0.1013	0.33372	0.541
AC30	0.3000	0.3333	0.6194	0.729314	0.1900	0.1772	0.888	0.735
T90	1.700	1.485	0.543	0.457	0.7873	0.6076	0.12757	0.237
ER90	0.9600	0.9394	0.791	0.643	0.4027	0.2342	0.081980	0.189
AC90	0.7400	0.5455	0.404	0.412	0.4299	0.3734	0.4325	0.436

Notes: Summary of readmission rates in pre-CP and CP NSA and SA patients. P-values are shown adjusted for covariates (age, sex, care package, number of comorbidities, index admission length of stay, and mental illness) and not adjusted.

Abbreviations: SA, substance abuse; NSA, nonsubstance abuse; CP, care package; T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days.

Table S4 Summary of effect of sex on readmissions

Readmission	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value
	Females	Males
T30	0.3257	0.4251	0.20001	0.204
ER30	0.1829	0.1777	0.9528	0.926
AC30	0.1429	0.2474	0.0210	0.025545
T90	0.8629	0.8815	0.781237	0.892
ER90	0.4171	0.4599	0.67975	0.694
AC90	0.4457	0.4564	0.7397	0.884

Notes: Summary of readmission rates in male and female patients. P-values are shown adjusted for covariates (age, care package, number of comorbidities, index admission length of stay, substance abuse, and mental illness) and not adjusted.

Abbreviations: T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days.

Table S5 Summary of effect of CP on readmissions depending on sex

Readmission	Females				Males
	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value	Average number of readmissions per patient		Adjusted P-value	Unadjusted P-value
	Pre-CP	CP			Pre-CP	CP
T30	0.3750	0.2658	0.3672	0.315	0.4229	0.4286	0.9879	0.957
ER30	0.2396	0.1139	0.17592	0.153	0.1714	0.1875	0.97971	0.819084
AC30	0.1354	0.1519	0.711	0.758163	0.2514	0.2411	0.9604	0.877
T90	1.073	0.6076	0.0205	0.0174	0.8914	0.8661	0.721703	0.89
ER90	0.6042	0.1899	0.00414	0.00376	0.4514	0.4732	0.936407	0.884
AC90	0.4688	0.4177	0.690	0.654	0.4971	0.3929	0.23441	0.269

Notes: Summary of readmission rates in pre-CP and CP male and female patients. P-values are shown adjusted for covariates (age, number of comorbidities, index admission length of stay, substance abuse, and mental illness) and not adjusted.

Abbreviations: CP, care package; T30, total readmissions in 30 days; ER30, emergency room readmissions in 30 days; AC30, acute care readmissions in 30 days; T90, total readmissions in 90 days; ER90, emergency room readmissions in 90 days; AC90, acute care readmissions in 90 days.