**1. Introduction**

Chronic obstructive pulmonary disease (COPD) is one of the chronic airway diseases, which characterized by the limitation in airflow and not fully reversible [1]. The reported prevalence of COPD is different among regions: 4% in Europe [2], 6.3% in the Asia Pacific region [3], from less than 4% to over 9% [4] in the US and predicted, with limited epidemiological evidence, to be at about 11% in 2010 in the African region [5,6].

This chronic disease has significant adverse effects on physical and mental conditions of those patients [7–9], as other systems and organs other than the lungs suffered the negative impacts, leading to pneumonia [10], pulmonary hypertension [11], and cardiovascular disease (CVD) [12]. A worsening mental status has been found in patients with COPD compared to non-COPD subjects, with higher rates of anxiety and depression [13,14], and the severity of fatigue [15]. Patients with COPD less frequently report a partner compared to others, and, when having a partner, they were less likely to be 'very satisfied' with the daily support and less often perceived emotional support from the partner [16]. They suffer worse quality of life with early-morning and nighttime symptoms compared to those without COPD [17,18]. COPD often results in a reduction in quality of life.

Quality of life (QoL) is defined by World Health Organization as a broad and complex concept of an individual about their physical health, mental health, social relationships and beliefs in the context of their living enviroment [19]. It is a "multidimensional measure" which focus on at least three domains: physics, psychology and society. Thus, several studies applied dimensions of QoL to to: (1) evaluate the efficiency of clinical therapies [20–22] or alternative therapies [23,24]; (2) identify factors associated with QoL [25] and increase health service quality [24]. In the case of COPD, improving QoL of patients with COPD becomes critical due to the incurables [26]. Medical methods have been used mainly to control COPD and strengthen prevention efforts, such as: (1) smoking cessation [27,28], (2) pharmacotherapy [29], and (3) Non-pharmacological therapy [30]. Therefore, measuring QoL could be useful in applying suitable interventions and preventing risk factors affected COPD.

Systematic reviews of interventions and treatments are considered as a reliable source of evidence to inform clinical practice and policy development [31]. Several systematic reviews and meta-analyses mentioning interventions to patients with COPD have been conducted. Gregersen et al. confirmed that telehealth showed promise for improving QoL of patients living with COPD, yet, this method call for more research to prove its effectiveness [32]. According to Coronini-Cronberg et al., psychosocial and pharmacological support is an effective intervention for smoking cessation [33], which raises the QoL in some health domains [34]. Moreover, breathing exercises can be used to improve the QoL of patients living with COPD, yet, the use of this method as a complementary therapy needs more research [35]. These literature review studies answer specific questions by gathering available empirical research evidence. However, a limitation of this approach is that it could review one method, which makes it difficult to compare the effects of all methods during a long period of study.

In addition, several researchers have used indicators of scientometric to review literature [36]. Prvevious studies used bibliometrics to explore research output, country collaboration, journal ranking or fundings of all papers mentioning COPD in European countries [37] or in Arab countries [38]. However, scientometric analyses may not have a deep understanding of the context of research or the landscape of research areas. Therefore, by combining scientometric and Latent Direcht allocation, topic modeling (in titles and abstracts), this study aims to describe the global trend in research outputs, countries collaboration, interdisciplinary research areas, as well as ten common topics among papers mentioning interventions to improve QoL of patients with COPD. The findings will emphasize research gaps, and make it possible to recommend some implications for future studies and policy.
