Immunogenicity of SARS-CoV-2 vaccines BBV152 (COVAXIN®) and ChAdOx1 nCoV-19 (COVISHIELD™) in seronegative and seropositive individuals in India: a multicentre, nonrandomised observational study.

Background: There are limited global data on head-to-head comparisons of vaccine platforms assessing both humoral and cellular immune responses, stratified by pre-vaccination serostatus. The COVID-19 vaccination drive for the Indian population in the age group 18-45 years began in April 2021 when seropositivity rates in the general population were rising due to the delta wave of COVID-19 pandemic during April-May 2021. Methods: Between June 30, 2021, and Jan 28, 2022, we enrolled 691 participants in the age group 18-45 years across four clinical sites in India. In this non-randomised and laboratory blinded study, participants received either two doses of Covaxin® (4 weeks apart) or two doses of Covishield™ (12 weeks apart) as per the national vaccination policy. The primary outcome was the seroconversion rate and the geometric mean titre (GMT) of antibodies against the SARS-CoV-2 spike and nucleocapsid proteins post two doses. The secondary outcome was the frequency of cellular immune responses pre- and post-vaccination. Findings: When compared to pre-vaccination baseline, both vaccines elicited statistically significant seroconversion and binding antibody levels in both seronegative and seropositive individuals. In the per-protocol cohort, Covishield™ elicited higher antibody responses than Covaxin® as measured by seroconversion rate (98.3% vs 74.4%, p < 0.0001 in seronegative individuals; 91.7% vs 66.9%, p < 0.0001 in seropositive individuals) as well as by anti-spike antibody levels against the ancestral strain (GMT 1272.1 vs 75.4 binding antibody units/ml [BAU/ml], p < 0.0001 in seronegative individuals; 2089.07 vs 585.7 BAU/ml, p < 0.0001 in seropositive individuals). As participants at all clinical sites were not recruited at the same time, site-specific immunogenicity was impacted by the timing of vaccination relative to the delta and omicron waves. Surrogate neutralising antibody responses against variants-of-concern including delta and omicron was higher in Covishield™ recipients than in Covaxin® recipients; and in seropositive than in seronegative individuals after both vaccination and asymptomatic infection (omicron variant). T cell responses are reported from only one of the four site cohorts where the vaccination schedule preceded the omicron wave. In seronegative individuals, Covishield™ elicited both CD4+ and CD8+ spike-specific cytokine-producing T cells whereas Covaxin® elicited mainly CD4+ spike-specific T cells. Neither vaccine showed significant post-vaccination expansion of spike-specific T cells in seropositive individuals. Interpretation: Covishield™ elicited immune responses of higher magnitude and breadth than Covaxin® in both seronegative individuals and seropositive individuals, across cohorts representing the pre-vaccination immune history of most of the vaccinated Indian population. Funding: Corporate social responsibility (CSR) funding from Hindustan Unilever Limited (HUL) and Unilever India Pvt. Ltd. (UIPL).

Isolated small airways obstruction predicts future chronic airflow obstruction: a multinational longitudinal study.

BACKGROUND: Chronic airflow obstruction is a key characteristic of chronic obstructive pulmonary disease. We investigated whether isolated small airways obstruction is associated with chronic airflow obstruction later in life. METHODS: We used longitudinal data from 3957 participants of the multinational Burden of Obstructive Lung Disease study. We defined isolated small airways obstruction using the prebronchodilator mean forced expiratory flow rate between 25% and 75% of the forced vital capacity (FVC) (FEF25-75) if a result was less than the lower limit of normal (

Feasibility and acceptability of the paediatric pulse oximeter in integrated management of neonatal and childhood illnesses (IMNCI) services by public health facilities: A qualitative study in rural Western India.

Background: Pneumonia contributes to about 15% of child deaths globally, with 20% of the overall deaths occurring in India. Although WHO recommends the use of pulse oximeters (PO) in first-level facilities for early detection of child pneumonia in low- and middle-income countries (LMICs), this has not yet been implemented in India. We aimed to assess the feasibility and acceptability of introducing PO in integrated management of neonatal and childhood illnesses (IMNCI) services at primary health centres (PHC) in the rural Pune district. Methods: We identified medical officers (MO) and auxiliary nurse midwives (ANM) from six PHCs as study participants due to their involvement in the treatment of children. We developed in-depth interview (IDI) guides for both groups to explore their IMNCI knowledge and attitude towards the program through a qualitative study. We conducted interviews with MOs (n = 6) and ANMs (n = 6) from each PHC. The PO module was added to explore perceptions about its usefulness in diagnosing pneumonia. After baseline assessment, we conducted training sessions on adapted IMNCI services (including PO use) for MOs and ANMs. PO devices were provided at the study PHCs. Results: At baseline, no PO devices were being used at study PHCs; PHC staff demonstrated satisfactory knowledge about paediatric pneumonia management and demanded refresher IMNCI training. They also felt the need to reiterate the PO use for early diagnosis of pneumonia in children and highlighted the challenges encountered in managing pneumonia at PHCs, such as health system-related challenges and parents' attitudes towards care seeking. There was positive acceptance of training and PO started to be used immediately in PHCs. There was increased confidence in using PO at endline. PO use in examining symptomatic children increased from 26 to 85%. Conclusions: Paediatric PO implementation could be integrated successfully at PHC levels; we found pre-implementation training and provision of PO to PHCs to be helpful in achieving this goal. This intervention demonstrated that an algorithm to diagnose pneumonia in children that included PO could improve case management.

Needs assessment for introducing pulmonary rehabilitation for chronic obstructive pulmonary disease management in a rural Indian setting: a qualitative study.

BACKGROUND: Pulmonary rehabilitation (PR) is an effective strategy to improve breathlessness, health status and exercise tolerance and to reduce readmissions and mortality. In India, there is no government health programme for chronic obstructive pulmonary disease (COPD) management while in the private sector availability of PR is limited. Most PR centres are in urban areas, with few services accessible to rural populations. We aimed to assess the need for PR from the perspective of patients with COPD and healthcare professionals (HCPs: registered medical practitioners and medical officers) in rural Maharashtra. METHODOLOGY: Between June and October 2020, we conducted semi-structured interviews with 14 patients with COPD and 9 HCPs to explore their perceptions of, and need for, PR in rural Maharashtra. Interviews were transcribed and analysed thematically. RESULTS: We approached 14 patients with COPD and 9 HCPs practising in rural areas. Five HCPs stated that they did not advise PR for patients with COPD citing poor compliance to PR referral and follow-up of the patients. Patients with COPD had symptoms and needs that could be helped by PR but commented how transportation would be a problem for them to visit a PR centre. In contrast, they could understand the benefits of PR and expressed their willingness to join such programmes. A PR service was established that addressed these needs. CONCLUSION: Patients with COPD have unmet needs that could benefit from attending a PR programme, but there are barriers at both healthcare and patient levels that we addressed in a new PR service for people with chronic respiratory disease in rural Maharashtra.

Seroprevalence of SARS-CoV-2 specific Immunoglobin G antibodies in rural population of Western Maharashtra, India.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, responsible for the coronavirus disease 2019 (COVID-19) pandemic, has been a major public health concern requiring continuous efforts for understanding its epidemiology. Patients infected with SARS-CoV-2 have a wide range of clinical features ranging from asymptomatic infection to mild or severe illness with fatal outcomes or recovery. Population-based seroepidemiological studies are an effective method for measuring the rapid spread of SARS-CoV-2 and monitoring the pandemic's progress. Methods: We conducted repeated cross-sectional community-based sentinel surveillance between January and June 2021 in the rural parts of the Pune district of Maharashtra, India to assess the seroprevalence against SARS-CoV-2 in three age categories. We selected 30 clusters for each round using a proportional population sampling method and 30 individuals in each of the three age groups (1-17 years, 18-49 years, and ≥50 years). We took blood samples from consenting study participants to check for the presence of Immunoglobulin G (IgG) antibodies against SARS-CoV-2 in all five rounds. Results: We included 14 274 individuals across five rounds; 29% were from the 1-17, 39% from the 18-49, and 32% from the ≥50-year-old group. Overall seroprevalence combining all rounds was 45%. There was an increase in seropositivity in rounds four (51.15%) and five (58.32%) contributed mostly by adults. We found that about 72% of elderly individuals ≥50 years in round five were seropositive. The factors strongly associated with the seropositivity were being in contact with suspected or confirmed cases of COVID-19 (odds ratio (OR) = 7.15; 95% confidence interval (CI) = 4.2-12.14), receiving at least one dose of COVID-19 vaccine (OR = 3.13 (95% CI = 0.70-14.07), being aged ≥50 years (OR = 1.97; 95% CI = 1.81-2.15), and being in an occupation belonging to a high-risk category (OR = 1.92; 95% CI = 1.65-2.26). Among 135 hospitalizations reported due to COVID-19-like illness, 91 (67%) were in the elderly age group of ≥50 and 33 (24%) were in the 18-49-year-old age group. Conclusions: Seroprevalence of SARS-CoV-2 was high in the last two rounds (April to June 2021) which coincide with the second wave of the pandemic (Delta variant B.1.617.2) in India. Overall, one in three children and one in two adults had antibodies for SARS-CoV-2. The suspected or confirmed case of COVID-19 emerged as the significant factor strongly associated with the seropositivity followed by COVID-19 vaccination.

Comparative outcome of transjugular intrahepatic portosystemic shunt with or without variceal obliteration: a systematic review and meta-analysis.

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) has been used for the secondary prevention of variceal bleeding. TIPS can be combined with variceal embolization (TIPS-VO), but its benefit remains controversial. The present systematic review and meta-analysis were conducted to compare the incidence of rebleeding, adverse events, and mortality among patients with TIPS alone and with TIPS-VO. METHODS: A literature search from January 2000 to June 2022 was done for studies comparing the outcome of patients undergoing TIPS alone or TIPS-VO. A subgroup analysis was conducted for patients undergoing TIPS with covered stents. RESULTS: A total of 11 studies with data from 1044 patients were included. The incidence of rebleeding was significantly higher in the TIPS alone group in both overall population OR 2.01 (1.42-2.83) and the subgroup (OR 1.92, 95% CI 1.21-3.04). There was no difference between the two groups concerning the risk of hepatic encephalopathy (OR 1.15, 95% CI 0.83-1.59), procedural adverse events (OR 0.86, 95% CI 0.54-1.39), shunt dysfunction (OR 1.20, 95% CI 0.82-1.75), overall mortality (OR 1.03, 95% CI 0.73-1.46), and mortality due to variceal rebleeding (OR 1.58, 95% CI 0.44-5.64). There was no significant heterogeneity or publication bias among the included studies. The certainty of evidence remains low for all the outcome expect for variceal rebleeding. CONCLUSION: The present meta-analysis provides a moderate-quality evidence for the benefit of TIPS-VO in reducing the incidence of rebleeding. However, the decision for combining variceal embolization with TIPS should be made on a case-to-case basis.

Changes in immunological parameters by ageing in rural healthy Indian adults and their associations with sex and lifestyle.

Several factors including sex and lifestyle have been reported to contribute to the age-related alteration of immune functions. The study was undertaken to determine age-related differences in the proportion of peripheral blood mononuclear lymphocytes in the Indian population using blood samples from 67 healthy adults (33 females and 34 males) aged between 20 and 80 years old. In the linear regression analysis to estimate the relationship with age categories, there was a significant increase in the frequency of natural killer cells with ageing, while their cytolytic activity significantly declined. The frequency of CD4+ T cells increased with age, whereas that of CD8+ T cells decreased, resulting in the age-associated increase of the CD4/CD8 ratio. The subsets of B cells did not show any significant relationship with age. Although there were variations between the male and female subgroups in effect size of ageing, the trends were in the same direction in all the parameters. Reduced fat intake was associated with a lower frequency of CD4+ T cells, and higher serum cotinine level was associated with a higher CD4/CD8 ratio. The results indicate that cellular immunity in the Indian population is affected by ageing, while humoral immunity is less susceptible to ageing.

Effectiveness of home-based pulmonary rehabilitation: systematic review and meta-analysis.

INTRODUCTION: Despite proven effectiveness for people with chronic respiratory diseases, practical barriers to attending centre-based pulmonary rehabilitation (centre-PR) limit accessibility. We aimed to review the clinical effectiveness, components and completion rates of home-based pulmonary rehabilitation (home-PR) compared to centre-PR or usual care. METHODS AND ANALYSIS: Using Cochrane methodology, we searched (January 1990 to August 2021) six electronic databases using a PICOS (population, intervention, comparison, outcome, study type) search strategy, assessed Cochrane risk of bias, performed meta-analysis and narrative synthesis to answer our objectives and used the Grading of Recommendations, Assessment, Development and Evaluations framework to rate certainty of evidence. RESULTS: We identified 16 studies (1800 COPD patients; 11 countries). The effects of home-PR on exercise capacity and/or health-related quality of life (HRQoL) were compared to either centre-PR (n=7) or usual care (n=8); one study used both comparators. Compared to usual care, home-PR significantly improved exercise capacity (standardised mean difference (SMD) 0.88, 95% CI 0.32-1.44; p=0.002) and HRQoL (SMD -0.62, 95% CI -0.88--0.36; p<0.001). Compared to centre-PR, home-PR showed no significant difference in exercise capacity (SMD -0.10, 95% CI -0.25-0.05; p=0.21) or HRQoL (SMD 0.01, 95% CI -0.15-0.17; p=0.87). CONCLUSION: Home-PR is as effective as centre-PR in improving functional exercise capacity and quality of life compared to usual care, and is an option to enable access to pulmonary rehabilitation.

Prioritising primary care respiratory research needs: results from the 2020 International Primary Care Respiratory Group (IPCRG) global e-Delphi exercise.

Respiratory diseases remain a significant cause of global morbidity and mortality and primary care plays a central role in their prevention, diagnosis and management. An e-Delphi process was employed to identify and prioritise the current respiratory research needs of primary care health professionals worldwide. One hundred and twelve community-based physicians, nurses and other healthcare professionals from 27 high-, middle- and low-income countries suggested 608 initial research questions, reduced after evidence review by 27 academic experts to 176 questions covering diagnosis, management, monitoring, self-management and prognosis of asthma, COPD and other respiratory conditions (including infections, lung cancer, tobacco control, sleep apnoea). Forty-nine questions reached 80% consensus for importance. Cross-cutting themes identified were: a need for more effective training of primary care clinicians; evidence and guidelines specifically relevant to primary care, adaption for local and low-resource settings; empowerment of patients to improve self-management; and the role of the multidisciplinary healthcare team.

A survey of the training and working arrangements of general practitioners providing asthma and chronic obstructive pulmonary disease care in a rural area of Maharashtra State.

Background: Chronic respiratory diseases (CRD), especially asthma and chronic obstructive pulmonary disease (COPD), are common public health problems resulting in a substantial burden of disease for individuals. There is a need to understand the perceptions and practices of primary care physicians ("general practitioners [GPs]") who provide most of the health care in rural India. We surveyed all private and public practitioners listed as practising in a rural area of Western India with the aim of identifying GPs (GPs: graduates, registered and allowed to practice in India) to understand their training, working arrangements, and asthma/COPD workload. Methodology: We administered a short questionnaire at educational meetings or via e-mail to all private and public practitioners listed as providing community-based services in the Junnar block, Pune district, Maharashtra. The survey asked about qualifications, experience, and working arrangements, and about current asthma and COPD workload. A descriptive analysis was performed. Results: We approached 474 practitioners (434 from private sector and 40 from public sector). Eighty-eight were no longer practising in the study area. The response rate was 330/354 (93.2%) of private and 28/32 (87.5%) of public sector practitioners. We excluded 135 nonrespiratory hospital specialists and 23 private practitioners whose highest qualification was a diploma. Our final sample of 200 GPs (70% males) was 177 from private sector and 23 from public sector. The private GPs had more experience in clinical practice in comparison to public GPs (18.6 vs. 12.8 years). Eighty-four percent of GPs from the private sector only had Ayurveda, Yoga, Naturopathy, Unani, Siddha, and Homoeopathy (AYUSH) qualifications, though >90% provided "modern medicine" services. In the public sector, 43.5% GPs only had AYUSH qualifications, though all provided "modern medicine" services. A minority (9% of private GPs and 16% of public GPs) provided both services. Nearly two-thirds (62%) of private GPs had inpatient facilities compared to only 9% of public sector GPs. In both sectors, more GPs stated that they managed people with asthma than treated COPD (Private: 97% vs. 75%; Public 87% vs. 57%). Conclusion: Many GPs practising "modern medicine" only had qualifications in Ayurveda/Homeopathy and fewer GPs are involved in the management of COPD as compared to asthma. These are important factors that form the context for initiatives seeking to improve the quality of community-based care for people with CRD in Maharashtra state in India.

Predictors for detecting chronic respiratory diseases in community surveys: A pilot cross-sectional survey in four South and South East Asian low- and middle-income countries.

BACKGROUND: Our previous scoping review revealed limitations and inconsistencies in population surveys of chronic respiratory disease. Informed by this review, we piloted a cross-sectional survey of adults in four South/South-East Asian low-and middle-income countries (LMICs) to assess survey feasibility and identify variables that predicted asthma or chronic obstructive pulmonary disease (COPD). METHODS: We administered relevant translations of the BOLD-1 questionnaire with additional questions from ECRHS-II, performed spirometry and arranged specialist clinical review for a sub-group to confirm the diagnosis. Using random sampling, we piloted a community-based survey at five sites in four LMICs and noted any practical barriers to conducting the survey. Three clinicians independently used information from questionnaires, spirometry and specialist reviews, and reached consensus on a clinical diagnosis. We used lasso regression to identify variables that predicted the clinical diagnoses and attempted to develop an algorithm for detecting asthma and COPD. RESULTS: Of 508 participants, 55.9% reported one or more chronic respiratory symptoms. The prevalence of asthma was 16.3%; COPD 4.5%; and 'other chronic respiratory disease' 3.0%. Based on consensus categorisation (n = 483 complete records), "Wheezing in last 12 months" and "Waking up with a feeling of tightness" were the strongest predictors for asthma. For COPD, age and spirometry results were the strongest predictors. Practical challenges included logistics (participant recruitment; researcher safety); misinterpretation of questions due to local dialects; and assuring quality spirometry in the field. CONCLUSION: Detecting asthma in population surveys relies on symptoms and history. In contrast, spirometry and age were the best predictors of COPD. Logistical, language and spirometry-related challenges need to be addressed.

Research priorities to address the global burden of chronic obstructive pulmonary disease (COPD) in the next decade.

BACKGROUND: The global prevalence of chronic obstructive pulmonary disease (COPD) has increased markedly in recent decades. Given the scarcity of resources available to address global health challenges and respiratory medicine being relatively under-invested in, it is important to define research priorities for COPD globally. In this paper, we aim to identify a ranked set of COPD research priorities that need to be addressed in the next 10 years to substantially reduce the global impact of COPD. METHODS: We adapted the Child Health and Nutrition Research Initiative (CHNRI) methodology to identify global COPD research priorities. RESULTS: 62 experts contributed 230 research ideas, which were scored by 34 researchers according to six pre-defined criteria: answerability, effectiveness, feasibility, deliverability, burden reduction, and equity. The top-ranked research priority was the need for new effective strategies to support smoking cessation. Of the top 20 overall research priorities, six were focused on feasible and cost-effective pulmonary rehabilitation delivery and access, particularly in primary/community care and low-resource settings. Three of the top 10 overall priorities called for research on improved screening and accurate diagnostic methods for COPD in low-resource primary care settings. Further ideas that drew support involved a better understanding of risk factors for COPD, development of effective training programmes for health workers and physicians in low resource settings, and evaluation of novel interventions to encourage physical activity. CONCLUSIONS: The experts agreed that the most pressing feasible research questions to address in the next decade for COPD reduction were on prevention, diagnosis and rehabilitation of COPD, especially in low resource settings. The largest gains should be expected in low- and middle-income countries (LMIC) settings, as the large majority of COPD deaths occur in those settings. Research priorities identified by this systematic international process should inform and motivate policymakers, funders, and researchers to support and conduct research to reduce the global burden of COPD.

Clinical effectiveness and components of Home-pulmonary rehabilitation for people with chronic respiratory diseases: a systematic review protocol.

INTRODUCTION: Chronic respiratory diseases (CRDs) are common and disabling conditions that can result in social isolation and economic hardship for patients and their families. Pulmonary rehabilitation (PR) improves functional exercise capacity and health-related quality of life (HRQoL) but practical barriers to attending centre-based sessions or the need for infection control limits accessibility. Home-PR offers a potential solution that may improve access. We aim to systematically review the clinical effectiveness, completion rates and components of Home-PR for people with CRDs compared with Centre-PR or Usual care. METHODS AND ANALYSIS: We will search PubMed, CINAHL, Cochrane, EMBASE, PeDRO and PsycInfo from January 1990 to date using a PICOS search strategy (Population: adults with CRDs; Intervention: Home-PR; Comparator: Centre-PR/Usual care; Outcomes: functional exercise capacity and HRQoL; Setting: any setting). The strategy is to search for 'Chronic Respiratory Disease' AND 'Pulmonary Rehabilitation' AND 'Home-PR', and identify relevant randomised controlled trials and controlled clinical trials. Six reviewers working in pairs will independently screen articles for eligibility and extract data from those fulfilling the inclusion criteria. We will use the Cochrane risk-of-bias tool and Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate the quality of evidence. We will perform meta-analysis or narrative synthesis as appropriate to answer our three research questions: (1) what is the effectiveness of Home-PR compared with Centre-PR or Usual care? (2) what components are used in effective Home-PR studies? and (3) what is the completion rate of Home-PR compared with Centre-PR? ETHICS AND DISSEMINATION: Research ethics approval is not required since the study will review only published data. The findings will be disseminated through publication in a peer-reviewed journal and presentation in conferences. PROSPERO REGISTRATION NUMBER: CRD42020220137.

Efficacy of transdermal delivery of liposomal micronutrients through body oil massage on neurodevelopmental and micronutrient deficiency status in infants: results of a randomized placebo-controlled clinical trial.

BACKGROUND: Micronutrient deficiency is a known cause of adverse neurodevelopment and growth. Poor adherence to oral regimes of micronutrient supplements is a known challenge during the implementation of supplementation programs. The present study evaluates the benefits of liposomal encapsulated micronutrient fortified body oils (LMF oil) that can be used for infant body massage in terms of neurodevelopment and prevention of deficiency. STUDY DESIGN: Double-blind randomized clinical trial. METHODS: A total of 444 healthy infants aged 4-7 weeks were randomized to receive either LMF oil (containing iron, vitamin D, folate, and vitamin B12) or placebo oil for gentle body massage till 12 months of age. Blood samples were collected at 6 and 12 months for transferrin saturation (TSAT), hemoglobin, and 25-hydroxy vitamin (25-OH-D) levels. Mental and motor development was assessed at 12 months using developmental assessment for Indian Infants (DASII). RESULTS: A total of 391 infants completed the study. There was no significant improvement in the hemoglobin in the intervention group at 12 months of age as compared to the placebo group [- 0.50 vs.-0.54 g%]. There was a marginally significant improvement in 25-OH-D at 12 months in the LMF oil group [+ 1.46vs.-0.18 ng/ml, p = 0.049]. In the subgroup of infants with moderate anemia, the intervention prevented the decline in hemoglobin at 12 months of age [adjusted mean change + 0.11vs.-0.51 g%, p = 0.043]. The mental or motor developmental quotients in the intervention group were not significantly different from those in the placebo group. CONCLUSION: Use of LMF oil for prevention of nutritional deficiency did not offer significant protection against nutritional anemia but prevented vitamin D deficiency to some extent with improvement in 25-OH-D at 12 months. In the subgroup of infants with moderate anemia, the intervention prevented the decline in hemoglobin at 12 months of age. The intervention did not result in significant improvement in mental or motor development. Further evaluation with increased doses needs to be undertaken. TRIAL REGISTRATION: CTRI no: CTRI/2017/11/010710 ; dated 30/11/2017.

Chronic respiratory disease surveys in adults in low- and middle-income countries: A systematic scoping review of methodological approaches and outcomes.

BACKGROUND: Chronic respiratory diseases (CRDs) contribute significantly towards the global burden of disease, but the true prevalence and burden of these conditions in adults is unknown in the majority of low- and middle-income countries (LMICs). We aimed to identify strategies - in particular the definitions, study designs, sampling frames, instruments, and outcomes - used to conduct prevalence surveys for CRDs in LMICs. The findings will inform a future RESPIRE Four Country ChrOnic Respiratory Disease (4CCORD) study, which will estimate CRD prevalence, including disease burden, in adults in LMICs. METHODS: We conducted a scoping review to map prevalence surveys conducted in LMICs published between 1995 and 2018. We followed Arksey and O'Malley's six-step framework. The search was conducted in OVID Medline, EMBASE, ISI Web of Science, Global Health, WHO Global Index Medicus and included three domains: CRDs, prevalence and LMICs. After an initial title sift, eight trained reviewers undertook duplicate study selection and data extraction. We charted: country and populations, random sampling strategies, CRD definitions/phenotypes, survey procedure (questionnaires, spirometry, tests), outcomes and assessment of individual, societal and health service burden of disease. RESULTS: Of 36 872 citations, 281 articles were included: 132 from Asia (41 from China). Study designs were cross-sectional surveys (n = 260), cohort studies (n = 11) and secondary data analysis (n = 10). The number of respondents in these studies ranged from 50 to 512 891. Asthma was studied in 144 studies, chronic obstructive pulmonary disease (COPD) in 112. Most studies (100/144) based identification of asthma on symptom-based questionnaires. In contrast, COPD diagnosis was typically based on spirometry findings (94/112); 65 used fixed-ratio thresholds, 29 reported fixed-ratio and lower-limit-of-normal values. Only five articles used the term 'phenotype'. Most studies used questionnaires derived from validated surveys, most commonly the European Community Respiratory Health Survey (n = 47). The burden/impact of CRD was reported in 33 articles (most commonly activity limitation). CONCLUSION: Surveys remain the most practical approach for estimating prevalence of CRD but there is a need to identify the most predictive questions for diagnosing asthma and to standardise diagnostic criteria.