TABLE 4.

Regression analyses examining potential risk factors and correlates of long-term nonadherence, n = 101 patients with data from original trial and follow-up assessment

			Nonadherence to:
	Total no. of areas of nonadherence		Taking medications		Attending clinic appointments		Performing spirometry		Monitoring blood pressure		Following diet/exercise requirements
Potential risk factors or correlatesa,b,c	β	95% CI	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI	OR	95% CI
Stage 1: Patient status at RCT baseline
Younger age at transplant, y	0.02	−0.01–0.04	1.01	0.97–1.04	1.02	0.99–1.05	1.04	0.99–1.09	1.04	1.01–1.09	0.98	0.95–1.01
Poorer caregiver support	−0.04	−0.68–0.59	0.36	0.11–1.16	0.90	0.37–2.22	2.07	0.62–6.93	0.83	0.33–2.06	1.31	0.53–3.23
Longer length of hospital stay after transplant	0.10	−0.32–0.53	1.39	0.68–2.84	1.07	0.58–1.97	0.73	0.34–1.56	1.63	0.88–2.99	0.94	0.53–1.74
Stage 2:d Patient status during first y posttransplant (period of original RCT)
Group assignment, Pocket PATH	0.10	−0.49–0.69	0.58	0.18–1.87	2.10	0.85–5.23	0.84	0.27–2.57	1.10	0.38–3.13	0.38	0.15–0.98
Longer total rehospitalization time during first y	−0.01	−0.28–0.25	0.73	0.43–1.23	1.31	0.87–1.96	0.99	0.59–1.66	0.47	0.29–0.78	1.26	0.80–1.99
Greater number of episodes of A2 or greater acute rejection during first y	0.47	0.08–0.86	2.68	1.24–5.80	0.97	0.52–1.79	3.07	1.17–8.03	2.10	1.03–4.28	1.62	0.82–3.19
Greater number of assessments indicating clinically significant anxiety during first y	0.36	0.07–0.65	2.30	1.29–4.10	1.33	0.86–2.07	1.17	0.66–2.10	1.65	0.98–2.80	1.42	0.88–2.29
Nonadherence at 1 y (end of trial)e	0.21	−0.03–0.45	2.31	0.57–9.36	-	-	1.13	0.36–3.51	2.47	0.89–6.88	3.11	1.08–8.99
Stage 3:d Patient status at time of follow-up assessment
Clinically significant anxiety at follow-up assessment	0.19	−0.45–0.83	0.90	0.27–2.99	1.93	0.72–5.17	1.47	0.42–5.16	0.73	0.24–2.20	0.68	0.23–2.05
R2 for complete modelf	0.22		0.31		0.13		0.19		0.32		0.27

^aOther variables that did not meet criteria for inclusion in final models were sex, race/ethnicity (non-Hispanic white vs all other groups), marital status at transplant, perceived self-care agency, internal locus of control, external locus of control, indication for transplantation, persistent depression during the first year posttransplant, acute rejection after the first year posttransplant, BOS, whether the patient had a family caregiver at follow-up, and the supportiveness of that relationship. Education and type of lung transplant were not eligible for inclusion due to very limited variability on these variables in the sample.

^bAlthough both clinically significant anxiety at follow-up and clinically significant depression at follow-up both met inclusion criteria for the final models, they were highly intercorrelated (r = 0.69) and thereby introduced a multicollinearity problem and instability in model parameter estimates (very large confidence intervals).⁵¹ We chose to report the model with anxiety at follow-up given that earlier levels of anxiety were also included in the models. However, repeating the modeling with depression at follow-up instead yielded similar results: it was not a statistically significant factor in any model

^cFactors with significant (P < 0.05) associations with outcomes are shown in bold font.

^dFor each outcome, the Stage 2 model adjusts for predictors entered at Stage 1, and the Stage 3 model adjusts for predictors entered at Stages 1 and 2.

^eFor each outcome, this predictor reflected previous nonadherence in the same area as the outcome (eg, previous medication taking if the outcome was medication-taking at follow-up). Nonadherence to clinic appointment attendance could not be included as a predictor because only 1 patient reported nonadherence in this area in the original RCT.

^fR² for linear regression (for total number of 8 areas of nonadherence) and Nagelkerke R² for logistic regressions (individual nonadherence outcomes).

BOS, bronchiolitis obliterans syndrome; CI, confidence interval; OR, odds ratio; Pocket PATH, pocket personal assistant for tracking health; RCT, randomized controlled trial.