Social determinants of intra-urban differentials of admissions by respiratory diseases in Salvador (BA), Brazil

Urbanisation and asthma in low-income and middle-income countries: a systematic review of the urban-rural differences in asthma prevalence

BACKGROUND

Urbanisation has been associated with temporal and geographical differences in asthma prevalence in low-income and middle-income countries (LMICs). However, little is known of the mechanisms by which urbanisation and asthma are associated, perhaps explained by the methodological approaches used to assess the urbanisation-asthma relationship.

OBJECTIVE

This review evaluated how epidemiological studies have assessed the relationship between asthma and urbanisation in LMICs, and explored urban/rural differences in asthma prevalence.

METHODS

Asthma studies comparing urban/rural areas, comparing cities and examining intraurban variation were assessed for eligibility. Included publications were evaluated for methodological quality and pooled OR were calculated to indicate the risk of asthma in urban over rural areas.

RESULTS

Seventy articles were included in our analysis. Sixty-three compared asthma prevalence between urban and rural areas, five compared asthma prevalence between cities and two examined intraurban variation in asthma prevalence. Urban residence was associated with a higher prevalence of asthma, regardless of asthma definition: current-wheeze OR:1.46 (95% CI:1.22 to 1.74), doctor diagnosis OR:1.89 (95% CI:1.47 to 2.41), wheeze-ever OR:1.44 (95% CI:1.15 to 1.81), self-reported asthma OR:1.77 (95% CI:1.33 to 2.35), asthma questionnaire OR:1.52 (95% CI:1.06 to 2.16) and exercise challenge OR:1.96 (95% CI:1.32 to 2.91).

CONCLUSIONS

Most evidence for the relationship between urbanisation and asthma in LMICs comes from studies comparing urban and rural areas. These studies tend to show a greater prevalence of asthma in urban compared to rural populations. However, these studies have been unable to identify which specific characteristics of the urbanisation process may be responsible. An approach to understand how different dimensions of urbanisation, using contextual household and individual indicators, is needed for a better understanding of how urbanisation affects asthma.

PROSPERO REGISTRATION NUMBER

CRD42017064470.

Free asthma medications reduces hospital admissions in Brazil (Free asthma drugs reduces hospitalizations in Brazil)

BACKGROUND

Since June 2011, the Brazilian health system started providing asthma medications (beclomethasone and salbutamol), totally free of charge to patients with asthma. The aim of this study was to evaluate the impact of the provision of free asthma medications on hospital admissions for asthma in Brazil, using a national hospitalization database (DATASUS), comparing the incidence of hospital admissions before and after the free supply of these drugs.

METHODS

Admissions of patients with 1-49 years of age by the Brazilian public health system with the diagnosis of asthma were compared pre (2008-2010) and post (2012-2014) provision of free medicines (beclomethasone and salbutamol). The number of hospital admissions due to asthma and non-respiratory diseases, as well as the amount spent with asthma hospitalization, were obtained from DATASUS, the Brazilian government open-access public health database system.

RESULTS

Admission rates for asthma significantly decreased from 90.09/100.000 (2008-2010) to 59.85/100.000 (2012-2014), when the period pre and post provision of free medicines were compared [OR 0.67 (CI 0.48-0.92)]. Non-respiratory admission rates remained stable, when both periods were also compared.

CONCLUSION

Asthma hospitalization rates significantly decreased in the three-year period after the provision of free medicines to treat asthma. Our findings suggest that the provision of free medications for asthma may have a particular public health impact by its own in developing countries.