International Journal of Noncommunicable Diseases

REVIEW ARTICLE
Year
: 2022  |  Volume : 7  |  Issue : 1  |  Page : 3--12

Chronic respiratory disease and coronavirus disease 2019 in developing countries: A systematic review


Ashutosh Nath Aggarwal, Ritesh Agarwal, Sahajal Dhooria, Kuruswamy Thurai Prasad, Inderpaul Singh Sehgal, Valliappan Muthu 
 Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
Dr. Ashutosh Nath Aggarwal
Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
India

Abstract

The proportion of coronavirus disease 2019 (COVID-19) patients having a chronic respiratory disease (CRD), and its impact on COVID-19 related patient outcomes, is unclear. We conducted this systematic review to evaluate the proportion of patients with asthma or chronic obstructive pulmonary disease (COPD) among COVID-19 patients, and to assess if comorbid CRD worsens COVID-19 outcomes, in developing countries. We queried PubMed database for studies conducted in developing countries and provided data on the proportion of COVID-19 patients with CRD, or severe disease or mortality among COVID-19 patients with and without CRD. We calculated proportion of CRD patients and relative risk (RR) for each reported outcome of interest. We used random-effects models to summarize our data. We retrieved 1947 citations and included 22 studies from developing countries in our review. The pooled estimate for proportion of asthma and COPD was 2.32% (95% confidence interval [CI] 1.86%–2.83%) and 3.52% (95% CI 2.14%–5.20%), respectively. COVID-19 patients with asthma had a higher risk of severe COVID-19 (summary RR 1.21, 95% CI 1.17–1.25), but not of mortality (summary RR 1.01, 95% CI 0.80–1.28), as compared to COVID-19 patients without asthma. COVID-19 patients with COPD had a higher risk of severe COVID-19 (summary RR 1.48, 95% CI 1.30–1.69) and mortality (summary RR 2.69, 95% CI 1.57–4.61), as compared to COVID-19 patients without COPD. Patients with asthma (but not COPD) in developing countries may be less likely to acquire COVID-19. Both diseases may increase the risk of severe COVID-19, and COPD may increase risk of COVID-19-related mortality.



How to cite this article:
Aggarwal AN, Agarwal R, Dhooria S, Prasad KT, Sehgal IS, Muthu V. Chronic respiratory disease and coronavirus disease 2019 in developing countries: A systematic review.Int J Non-Commun Dis 2022;7:3-12


How to cite this URL:
Aggarwal AN, Agarwal R, Dhooria S, Prasad KT, Sehgal IS, Muthu V. Chronic respiratory disease and coronavirus disease 2019 in developing countries: A systematic review. Int J Non-Commun Dis [serial online] 2022 [cited 2022 Jun 27 ];7:3-12
Available from: https://www.ijncd.org/text.asp?2022/7/1/3/342081


Full Text



 Introduction



The ongoing coronavirus disease 2019 (COVID-19) pandemic is spreading relentlessly, and has already affected nearly 290 million people globally (around 3.7% of the world population) by the end of 2021.[1] The USA, a developed nation, contributes most to this caseload (more than 55 million people affected), followed by India, a developing country (nearly 35 million people affected). Based on these estimates, about 16.7% of the US population, and about 2.5% of the Indian population can be considered to have had proven COVID-19 disease.[1] It is commonly believed that such officially notified information on COVID-19 is a gross underestimate, much more so from developing countries. The deficient health infrastructure in most developing nations is also more likely to get overwhelmed by the huge COVID-19 burden. The overall health and economic consequences from COVID-19 are therefore expected to be far worse for most developing countries.

Chronic respiratory diseases (CRDs) are associated with greater use of healthcare resources, significant morbidity, and a higher risk of death.[2] Asthma and chronic obstructive pulmonary disease (COPD) are the two most important CRDs of public health significance. The prevalence of both disorders shows great regional variability, although they are relatively more prevalent in high-income countries.[2] COPD contributes much more to global mortality and morbidity than asthma.[2] The relationship between CRDs and COVID-19 has been investigated in several studies and systematic reviews. A recent systematic review of 150 studies reported a much greater summary prevalence of asthma among COVID-19 patients in the USA (11.0%) as compared to Europe (7.6%) or Asia (1.9%).[3] However, in contrast to patients hospitalized with influenza, COVID-19 inpatients had a much lower prevalence of underlying asthma.[4] Nonetheless, asthma appears to have at best a marginal impact on adverse clinical outcomes such as severe COVID-19, need for hospitalization, intensive care unit (ICU) admission, or mortality.[3],[5] COPD, on the other hand, significantly worsens clinical outcomes among COVID-19 patients by a magnitude much larger than that for asthma.[6],[7],[8],[9],[10] Despite this, the prevalence of COPD might be lower than asthma among patients with COVID-19, and some reviews with a limited number of studies suggest wide variability in estimates with a summary prevalence of around 2%–3%.[7],[11],[12]

Most studies providing data on the prevalence and outcomes of CRDs in COVID-19 patients have been conducted in the USA, Europe, or China. There is little published data on this topic from the developing world.[13] A modeling study suggested that CRDs add to the population COVID-19 mortality in India, a developing nation with a high COVID-19 burden, by 1.88% relative to England, a developed nation.[14] Herein, we evaluate the frequency of concurrent CRDs (asthma or COPD) among COVID-19 patients in developing countries. We also assess if comorbid asthma or COPD increases the risk of severe disease or mortality in COVID-19 patients from these countries.

 Methods



We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Meta-analysis of Observational Studies in Epidemiology (MOOSE) recommendations for reporting our review.[15],[16] An approval from our Institutional Ethics Committee was not necessary as we extracted only summary information from previously published articles.

Search strategy

We queried the PubMed electronic database for publications indexed till July 31, 2021, using the following search string: (“CRD” OR asthma OR “COPD” OR COPD) AND (COVID-19 OR severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]), without imposing any geographic, temporal, or linguistic restrictions. We also examined the bibliographies of selected articles and recent reviews for additional relevant publications.

Selection of studies

Two reviewers (ANA and RA) initially screened all the titles and abstracts. We omitted publications not reporting on COVID-19 or CRDs. We also excluded experimental, radiological or autopsy studies, case reports, letters to editor not describing original observations, reviews, guidelines, editorials, and study protocols. Full texts of citations considered potentially suitable by either reviewer were assessed further.

We included a publication for data synthesis if it (a) included at least 100 patients with COVID-19 from a developing country, confirmed by detection of novel SARS-CoV-2 RNA in respiratory specimens, or strongly suspected on clinical or radiological assessment if a confirmatory test was not available, or (b) either described the frequency of patients having concurrent asthma or COPD among COVID-19 patients or reported on disease severity or mortality as an outcome in COVID-19 patients with and without asthma or COPD. Severe COVID-19 was defined by a composite of patients needing hospital admission or having severe COVID-19 disease defined as per the prevalent World Health Organization or another guidance. In the absence of any universally accepted definition for a developing country, we adopted the World Bank approach (based on per capita gross national income) for the current 2022 fiscal year. Low-income and lower-middle-income economies were categorized as developing nations, and the other high-income or upper-middle-income economies as developed nations.[17] Publications from other countries, or multi-country studies, were not included. We also excluded articles not reporting outcomes of interest, or studies providing information from highly specific patient subgroups (e.g., patients on dialysis, cancer patients, or ICU patients). If the same (or substantially overlapping) patient cohort was reported in two or more publications, we included the one describing the largest patient population. In case of any disagreement, consensus between the two reviewers determined study inclusion.

Data extraction and study quality

We obtained information on study design, location and healthcare setting, participant inclusion and exclusion criteria, period of patient enrollment, the source of patient information, and the outcomes reported, from all eligible studies. We used the Newcastle-Ottawa Scale (NOS) to assess the methodological quality of studies.[18] We considered a study to be of good quality if its NOS score was seven or more (out of a maximum possible score of nine).

Statistical analysis

We acquired the national asthma and COPD prevalence rates from estimations projected for various countries by the Global Burden of Disease (GBD) collaborators.[19] We estimated the percentage of asthma and COPD patients among those with COVID-19 disease in each study and calculated the corresponding 95% confidence interval (95% CI) by Clopper–Pearson exact method.[20] We also computed the relative risk (RR), and the corresponding 95% CI, for each predefined outcome from each study.[21] We decided on a continuity correction of 0.5 for studies having “zero” cell frequencies prior to these calculations.

We pooled our data using the DerSimonian-Laird random-effects model to generate summary estimates.[22] Freeman-Tukey double arcsine transformation was used to summarize data on proportions.[23] We assessed between-study heterogeneity through the Higgins' inconsistency index (I2), which was considered high for values greater than 0.75.[24] Publication bias was assessed through Eggers' test and by visualizing contour-enhanced trim-and-fill funnel plots.[25],[26] We utilized the statistical software Stata (Intercooled edition 12.0, Stata Corp, USA) for analyzing our data.

 Results



We identified 1937 publications from our literature search and included ten additional studies from other sources [Figure 1]. We finally selected 22 studies, describing 282,534 patients with COVID-19, for data synthesis.[27],[28],[29],[30],[31],[32],[33],[34],[35],[36],[37],[38],[39],[40],[41],[42],[43],[44],[45],[46],[47],[48] The main attributes of these studies are summarized in [Table 1]. Nine (40.9%) of them also provided information to calculate RR for one or both of the adverse clinical outcomes of interest [Table 2].[31],[35],[36],[37],[39],[43],[44],[45],[47] There were 16 (72.7%) publications from Asia, five (22.7%) from Africa, and one (4.5%) from Central America, with maximum contribution from Iran (nine studies) [Table 1]. All studies evaluated data from retrospective patient cohorts, except for two (9.1%) that collected the information prospectively.[29],[30] Two (9.1%) studies reported population-based data, while the others were conducted in a hospital setting.[35],[48] One (4.5%) study also included COVID-19 patients based on high radiological suspicion.[30] All others only studied patients with disease confirmed by the detection of SARS-CoV2 RNA in respiratory specimens. Patient information was retrieved mainly from medical records at participating healthcare facilities, or also from patient interviews in two studies [Table 1].[36],[47] All except three (13.6%) studies were considered high quality [Table 1].[36],[37],[39]{Figure 1}{Table 1}{Table 2}

Proportion of patients with chronic respiratory diseases

The proportion of COVID-19 patients having asthma or COPD could be computed from all 22 studies. It ranged from 0.63% to 8.93% for asthma, and from 0.44% to 12% for COPD [Table 2]. The highest occurrence for asthma was reported from a small Iranian study, while the highest occurrence for asthma was noted in a study conducted in Bangladesh.[39],[43]

Sixteen studies provided information on the proportion of asthmatics among COVID-19 patients. Twelve (75.0%) of these estimates were lower than their corresponding GBD country estimates for population prevalence of asthma [Figure 2]. The pooled proportion estimate from all 16 studies was 2.32% (95% CI 1.86%–2.83%). This was lower than the median national asthma prevalence in the countries where these studies were conducted (3.13, interquartile range 2.37–3.59) [Table 2]. There was substantial heterogeneity between the studies (I2 95.4%). Omitting the study with the highest outlier asthma prevalence resulted in a slightly lower summary estimate of proportion (2.18%, 95% CI 1.74%–2.67%) with no reduction in heterogeneity (I2 95.4%).[43] On sensitivity analysis, omitting other studies one at a time also did not appreciably influence summary estimates or heterogeneity. There was no significant publication bias.{Figure 2}

Fourteen studies reported data on proportion of COPD patients among those with COVID-19. All except two (14.3%) of these estimates were higher than their corresponding GBD country estimates for population prevalence of COPD [Figure 2].[35],[46] The pooled proportion estimate from all 14 studies was 3.52% (95% CI 2.14%–5.20%). This was higher than the median national COPD prevalence in the countries where these studies were conducted (1.85, interquartile range 1.67–2.04) [Table 2]. There was substantial heterogeneity between the studies (I2 98.1%). Omitting the study with the highest outlier COPD prevalence resulted in a slightly lower summary estimate of proportion (3.16%, 95% CI 1.84%–4.80%) with no change in heterogeneity (I2 98.2%).[39] On sensitivity analysis, omitting other studies one at a time also did not appreciably influence summary estimates or heterogeneity. There was no significant publication bias.

Severe COVID-19

Two studies with 205,767 COVID-19 patients, of whom 2,741 (1.3%) had asthma, provided information on severe COVID-19 among asthmatics.[44],[45] Both these publications were from Iran, had a retrospective design, and included patients with laboratory-confirmed COVID-19. Both studies were considered high quality. Of the 99,172 patients with severe disease in the included cohorts, 1591 (1.6%) had underlying asthma. Only the larger study reported a RR for severe COVID-19 that significantly exceeded 1.0 [Figure 3].[45] COVID-19 patients who also had asthma were 1.21 (95% CI 1.17–1.25) times more likely to develop severe COVID-19 as compared to COVID-19 patients without asthma [Figure 3]. This summary RR estimate was almost solely driven by the larger study.[45] There was negligible heterogeneity between the studies (I2 0%). There was no significant publication bias.{Figure 3}

In addition, two studies with 609 COVID-19 patients, of whom 48 (7.9%) had COPD, provided information on severe COVID-19 among COPD patients.[31],[44] One each of these publications was from Egypt and Iran. Both had a retrospective design and included hospitalized patients with laboratory-confirmed COVID-19. Both studies were considered high quality. Of the 322 patients with severe disease in the included cohorts, 36 (11.2%) had underlying COPD. Only the larger study reported a RR for severe COVID-19 that significantly exceeded 1.0 [Figure 3].[31] COVID-19 patients who also had COPD were 1.48 (95% CI 1.30–1.69) times more likely to develop severe COVID-19 as compared to COVID-19 patients without COPD [Figure 4]. This summary RR estimate was almost solely driven by the larger study.[31] There was negligible heterogeneity between the studies (I2 0%). There was no significant publication bias.{Figure 4}

Mortality

Five studies with 243,128 COVID-19 patients, of whom 3,592 (1.5%) had asthma, reported on deaths due to COVID-19.[35],[37],[43],[44],[45] Three (60.0%) of these were conducted in Iran.[37],[44],[45] All studies had a retrospective design and included patients with laboratory-confirmed COVID-19. Only one (20.0%) of these studies was not considered as good quality.[37] Of the 27,310 patients who died in the included cohorts, 438 (1.6%) had underlying asthma. Only one (20.0%) Iranian study reported RR for mortality that clearly exceeded 1.0.[37] COVID-19 patients who also had asthma were 1.01 (95% CI 0.80–1.28) times more likely to die as compared to COVID-19 patients without asthma [Figure 3]. There was moderate heterogeneity between the studies (I2 69.5%), and no clear outlier observation. On sensitivity analysis, omitting studies one at a time did not appreciably influence summary estimates or heterogeneity. There was no significant publication bias.

Six studies with 38,619 COVID-19 patients, of whom 835 (2.2%) had COPD, reported on deaths due to COVID-19.[35],[36],[37],[39],[44],[47] Half of these were conducted in Iran.[37],[39],[44] All studies had a retrospective design and included patients with laboratory-confirmed COVID-19. Only three (50.0%) studies were considered as high quality.[35],[44],[47] Of the 6,572 patients who died in the included cohorts, 232 (3.5%) had underlying COPD. All except one (16.7%) Iranian study reported RR for mortality that clearly exceeded 1.0 [Figure 4]. COVID-19 patients who also had COPD were 2.69 (95% CI 1.57–4.61) times more likely to die as compared to COVID-19 patients without COPD. There was substantial heterogeneity between the studies (I2 83.3%). Omitting the study with the highest outlier RR value resulted in a slightly lower summary RR estimate (2.20, 95% CI 1.3.9–3.50) with some reduction in heterogeneity (I2 74.0%).[36] On sensitivity analysis, omitting studies one at a time did not appreciably influence summary estimates or heterogeneity. There was no significant publication bias.

 Discussion



We found that 2.32% and 3.52% of the COVID-19 patients in the developing countries had concurrent asthma and COPD, respectively. These summary estimates of proportion were lower than corresponding median GBD country prevalence estimate for asthma and higher than corresponding median GBD country prevalence estimate for COPD. Asthmatics in these studies showed a higher risk for severe disease, but not for mortality, as compared to COVID-19 patients without asthma. In contrast, COPD patients in these studies showed a significantly higher risk for both severe disease and mortality, as compared to COVID-19 patients without COPD. Summary RR estimates for COPD were much higher than those for asthma.

In a recent review, we highlighted that the overall impact of comorbid asthma or COPD on adverse COVID-19 outcomes may be broadly similar between developed and developing nations.[13] Our current findings also largely mirror those from other recent systematic reviews that summarized information available mostly from the developed world. In a recent systematic review, we reported that asthmatics with COVID-19 had a marginally higher risk of hospitalization, but not for severe disease, ICU admission, mechanical ventilation, or mortality as compared to COVID-19 patients without asthma.[5] Another meta-analysis summarizing patient outcome data also found no clear pointers toward increased risk of hospitalization, ICU admission, or mortality due to asthma.[3] This meta-analysis also did not provide any clear evidence of increased risk of acquiring COVID-19 among asthmatics.[3] In contrast, few recent meta-analysis exploring the COVID-19-related outcomes in COPD patients have consistently demonstrated an association between COPD and higher mortality, and greater need for hospitalization, mechanical ventilation, and ICU admission in patients with COVID-19.[6],[8],[9]

Our systematic review has a few limitations. A major constraint identified through our analysis is the paucity of published literature from developing countries regarding interactions between CRDs and COVID-19. Even though we synthesized information from 22 studies from developing countries, we excluded 261 studies reporting data from developed nations [Figure 1]. This implies that less than 8% of studies identified through our literature search were conducted in developing countries. It is possible that such information is available through local or regional journals that we could not locate through the PubMed database. Although limited data points to only minor differences between developed and developing nations, uncertainties remain.[13] We obtained national-level estimates for CRDs to compare data reported in individual studies.[19] However, all such estimations suffer from some degree of imprecision. Moreover, they do not reflect variations between regions or subpopulations, especially in large or populous nations. Our categorization of developing and developed nations was based solely on economic criteria as a surrogate, whereas 'development' also has other social, educational, health, and technological facets. Due to the dynamic nature of the pandemic, and the lag between data collection and publication of results, most studies provide information from 2020 and from regions that may have been severely afflicted earlier. Thus, our numbers may not truly represent the more current patient profile from all the geographic locations. In addition, most of the included studies had a retrospective design and collated data from medical records that were likely completed in an overwhelmed health system [Table 1]. This could have resulted in both underreporting as well as misclassification of comorbid health conditions. There are several similarities in the presenting features of COVID-19 and exacerbations of CRDs. Both may present with subacute worsening of breathlessness, and many CRD exacerbation episodes are precipitated by pulmonary infections that may manifest with fever and cough. This can complicate decision-making, especially in nations with a high burden of CRDs. Several studies reported only on inpatients who have a higher probability of adverse outcomes compared to patients in the community. There were differences in healthcare strategies regarding SARS-CoV-2 testing and admission/transfer criteria, variability in institutional practices in the timing of investigations and other evaluations, and the level and extent of medical intervention available to patients. Such heterogeneity can restrict the generalizability of our results, even to other developing nations.

It is well known that the healthcare infrastructure and health delivery in several developing countries have proved quite inadequate in face of the COVID-19 onslaught. Researchers and health program managers from the developing world need to generate quality evidence from these regions to help determine the impact of COVID-19 and CRDs on each other. Such information will be extremely useful to design and implement appropriate mitigation strategies tailored to the requirements of developing countries.

 Conclusion



In summary, there is a paucity of evidence on CRD and COVID-19 interaction in developing countries. Limited data from developing countries suggest that patients with asthma (but not COPD) may be less likely to acquire COVID-19. Both asthma and COPD may increase the risk of severe COVID-19, and COPD may increase risk of COVID-19-related mortality.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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