Evaluation of Clinical Data and Mortality among COPD Patients Receiving Domiciliary NIMV Therapy

Received: 04.07. 2013 Accepted: 09.11. 2013 This study was presented as an oral presentation during the 15th Annual Congress of Turkish Thoracic society, 11-15 April 2012, Antalya, Turkey: ss-036. Address for Correspondence: Tacettin Örnek, Department of Chest Diseases, Bülent Ecevit University Faculty of Medicine, Zonguldak, Turkey Phone: +90 372 266 20 01 E-mail: tacettinornek@yahoo.com ©Copyright 2014 by Turkish Thoracic Society Available online at www.toraks. dergisi.org 112 ciliary NIMV for COPD. Patients who were prescribed NIMV for obesity hypoventilation syndrome or sleep apnoea syndrome were excluded. Therefore, 5 patients who were prescribed the device because of reasons other than COPD (restrictive lung disease due to scoliosis [n=1], interstitial pulmonary disease [n=2], obesity hypoventilation syndrome [n=2]) were excluded from the study (Figure 1). In April 2013, the patients were contacted using their phone numbers recorded in the electronic file system of the hospital and their consents were obtained after they were informed about the study. They were questioned whether they regularly used the device, daily duration of device use and death date if they died (information about dead patients were obtained from their legal representatives). Three patients who could not be reached and three patients who did not use the device regularly or used the device for less than 4 hours daily were excluded. The remaining 34 patients were considered as the study group. Clinical data of these patients were retrospectively reviewed using electronic patient files. statistical Analysis Data were analysed using the Statistical Package for the Social Sciences (SPSS) version 16.0 (Chicago, USA) package program. Normality of distribution was tested using the Kolmogorov-Smirnov test. The means of two dependent groups was compared by Wilcoxon Signed-rank test in case the distribution of the groups was not normal, and the PairedSamples T test (Student T test) was used in case of normal distribution. The means of two independent groups were compared by Mann-Whitney U test when the distribution of the groups was not normal, whereas categorical variables were compared using the chi-square test and, if appropriate, by Fisher’s Exact Probability test. Survival analysis was performed using Kaplan-Meier method. P<0.05 was considered statistically significant. resULTs The mean age of the patients was 68±15 (range, 34-87) years and 59% (n=20) were females. All females had a history of biomass exposure, whereas 45% (n=9) had a history of cigarette smoking. Of the males, 86% (n=12) had a history of cigarette smoking and the 2 non-smoker males were retired coal mine workers. Of the patients included in the study, 53% (n=18) were house wives and 24% (n=8) were retired coal mine workers. Clinical data of the patients are summarized in Table 1. As was expected, there was a significant difference between the blood gas values obtained at hospital admission and at hospital discharge in patients receiving domiciliary NIMV (Table 2). According to the Global Obstructive Lung Disease (GOLD) criteria, 35% were Stage 4, 24% were Stage 3, and 41% were Stage 2 patients [4]. None of the patients had GOLD Stage 1 disease. Mortality in patients receiving domiciliary NIMV therapy is presented in Table 3 and the survival curve is demonstrated in Figure 2. The mean age and the mean duration of daily NIMV use of patients with a lifespan≤2 years after domiciliary NIMV prescription were significantly higher (n=17) as compared to that of the patients with a lifespan>2 years (n=17) (Table 4). The median follow-up period of study participants was 17 (range, 1-39) months. The number of patients that survived for at least 1 year after the initiation of NIMV therapy was 21 (62%). In these patients, the mean number of hospitalizations before and after domiciliary NIMV therapy was 1.38±1.28 and 0.57±0.93, respectively (p=0.003). The mean daily duration of domiciliary NIMV use was 8.91±4.46 hours. Thirty eight percent (n=13) of the patients had been receiving long-term oxygen therapy (LTOT) previously. LTOT was commenced for the first time in 62% (n=21) of the patients together with NIMV. dIsCUssIoN In the present study, we discussed the clinical data and mortality of COPD patients that were discharged with domiciliary NIMV in the light of literature. The present study demonstrated that annual mortality in COPD patients receiving domiciliary NIMV therapy was 38.2%. Although NIMV therapy is frequently used for the treatment of chronic hypercapnic respiratory failure, data on the longterm efficacy of domiciliary NIMV therapy in COPD patients Figure 1. Flowchart illustrating the number of dropouts and the reasons COPD: Chronic obstructive pulmonary disease; NIMV: non-invasive mechanical ventilation Number of patients receiving domiciliary NIMV=45 NIMV=40 NIMV=37 Study group=34 Without COPD NİMV=5 Noncompliant =3 Could not be reached=3 Table 1. Clinical data of the patients receiving domiciliary NIMV