Depression in elderly outpatients with disabling chronic obstructive pulmonary disease

Age and Ageing, March, 1998 by Abebw M. Yohannes, Jamal Roomi, Robert C. Baldwin, Martin J. Connolly

Keywords: chronic obstructive pulmonary disease, depression, outpatients

Introduction

The chief symptom of chronic obstructive pulmonary disease (COPD) is dyspnoea but other commonly reported problems include tiredness, lethargy, anergia and altered libido and sexual function [1]. Depression is also common. It too may be disabling, ranking in its impact on quality of life alongside eight common and seriously disabling conditions, including diabetes, ischaemic heart disease and arthritis [2]. Depression in COPD is associated with additional disability [3] and a poorer quality of life [4].

The wide range of reported prevalence rates for depression in COPD reflects the difficulty in disentangling symptoms arising from COPD from similar symptoms caused by depression. Gift and McCrone [5] quote a median value of around 40% (point-prevalence) but it is unclear whether this rate is higher than that associated with other debilitating diseases. The combination of unpredictable exacerbations and the burden of chronic illness may lead to more negative ideation and hence more depression than some other disabling conditions. Elderly people are most prone to COPD and sick older people are especially vulnerable to depression [6, 7]. This study examined the prevalence of depressive symptoms in elderly patients with COPD using a depression scale devised for use in older people with major physical illness.

Comparisons were made with similarly disabled elderly patients without COPD and a normal elderly control group. The null hypothesis was that depression is no more common in patients with COPD than in those with other chronic illnesses and that the prevalence in both groups is no higher than controls of equivalent ages. The study also explored the relationship between baseline measures of respiratory function, activities of daily living and disease-specific measures of quality of life and depression.

Methods

Subject selection

Subjects comprised 96 outpatients (including 85 attending day hospital) with symptomatic irreversible COPD (chronic asthma and smoking-related chronic airways obstruction). Fifty-six were men and the age range was 70-93 (mean 78) years. COPD was defined as the best 1-s forced expiratory volume ([FEV.sub.1]) being less than 70% of the predicted level and rising by less than 15% after 5mg nebulized salbutamol. COPD subjects were included if they were clinically stable with no change in medication for 1 month and no hospital admission in the previous 6 weeks.

Exclusion criteria for the subjects were acute or chronic confusion (Hodkinson Abbreviated Mental Test Score [is less than] 7/10 [8]), prior non-depressive psychiatric disease, use of oral steroids with past 6 weeks and refusal of consent.

Normal control subjects were chosen at random from those who had recently participated in a community survey in our department [9]. Of these, 55 (23 men) aged 71-90 (mean 78) years agreed to participate. Of the 16 who did not attend, three had died of non-respiratory problems, four were awaiting minor surgery and nine declined without giving a reason. The subjects in the original community survey were representative of the Central Manchester population who are in that age range in all respects except that there was a slight excess of women [9). Disabled controls were 53 (27 men) aged 71-92 (mean 78) years attending day hospital because of Parkinson's disease, stroke, arthritis and amputation and who had normal lung function.

All subjects gave written witnessed informed consent. The study was approved by the medical ethics committee of the Central Manchester Health Care Trust and Bury Health Authority.

Study design

The design was single blinded. History, examination and physiological measurements were performed by a consultant geriatrician and questionnaires were administered by a research physiotherapist. Investigators were blinded to each others' results during the study period. Subjects were seen as outpatients at the geriatric day hospital. [FEV.sub.1] and forced vital capacity (FVC) were measured using a compact C spirometer (Vitalograph, Buckingham, UK). Three reproducible readings ([+ or -] 5% [FEV.sub.1]) were taken at 1-min intervals and the best result recorded. The physiotherapist administered the Chronic Respiratory Questionnaire (CRQ) and Brief Assessment Schedule Depression Cards (BASDEC). Most subjects self-completed the Nottingham extended activities of daily living scale (NEADL) questionnaire. For those who had difficulty reading or writing, the physiotherapist read out the questionnaires and recorded their responses. The physiotherapist supervised and gave advice to the subjects on how to complete the questionnaires, but gave no advice either directly or indirectly that might influence their response to the questions.

We used a well-validated measure of activities of daily living, the NEADL, to quantify the degree of disability [10]. Likewise a disease-specific quality of life questionnaire, the CRQ, was used to ascertain the impact of airways obstruction on quality of life [11]. Validation of the CRQ was originally performed in random groups of COPD patients not selected for age (including elderly subjects) [11]. The 6-min walk test was used to assess exercise tolerance [12]. The BASDEC [13] was administered to investigate the prevalence of depressive ideation in all subjects. BASDEC has been previously employed as a screening tool for depression in elderly inpatients. A score of [is greater than or equal to] 7 on BASDEC is suggestive of depression (termed a `case') with a sensitivity of 71% and a specificity of 88% [13].