13. Otros

Donroe J, Tincopa M, Gilman RH, Brugge D, Moore DA.

PLoS One. 2008 Sep 10;3(9):e3166.

This research investigated personal and environmental risk factors for child pedestrian RTIs relevant to an urban, developing world setting. This is a case control study of personal and environmental risk factors for child pedestrian RTIs in San Juan de Miraflores, Lima, Perú. The analysis of personal risk factors included 100 cases of serious pedestrian RTIs and 200 age and gender matched controls. Demographic, socioeconomic, and injury data were collected. The environmental risk factor study evaluated vehicle and pedestrian movement and infrastructure at the sites in which 40 of the above case RTIs occurred and 80 control sites. Reducing traffic volumes and speeds, limiting the number of street vendors on a given stretch of road, and improving lane demarcation should be evaluated as components of child pedestrian RTI interventions in poorer countries.

Martin, DL., Marks, M., Galdos-Cardenas, G., Gilman, RH., Goodhew, B., Ferrufino, L., Halperin, A., Sanchez, G., Verastegui, M., Escalante, P., Naquira, C., Levy, MZ., Bern, C..

Am J Trop Med Hyg. 2014 Jun;90(6)

Abstract

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major cause of morbidity and mortality in Central and South America. Geographic variations in the sensitivity of serologic diagnostic assays to T. cruzi may reflect differences in T. cruzi exposure. We measured parasite-specific T-cell responses among seropositive individuals in two populations from South America with widely varying antibody titers against T. cruzi. Antibody titers among seropositive individuals were significantly lower in Arequipa, Peru compared with Santa Cruz, Bolivia. Similarly, the proportion of seropositive individuals with positive T-cell responses was lower in Peru than Bolivia, resulting in overall lower frequencies of interferon-γ (IFNγ)-secreting cells from Peruvian samples. However, the magnitude of the IFNγ response was similar among the IFNγ responders in both locations. These data indicate that immunological discrepancies based on geographic region are reflected in T-cell responses as well as antibody responses.

© The American Society of Tropical Medicine and Hygiene.

Psaki, S., Seidman, J., Miller, M., Gottlieb, M., Bhutta, Z., Ahmed, T., Ahmed, A., Bessong, P., John, SM., Kang, G., Kosek, M., Lima, A., Shrestha, P., Svensen, E., Checkley, W.; MAL-ED Network Investigators.

Popul Health Metr. 2014 Mar 21;12(1)

Abstract

BACKGROUND:

There is no standardized approach to comparing socioeconomic status (SES) across multiple sites in epidemiological studies. This is particularly problematic when cross-country comparisons are of interest. We sought to develop a simple measure of SES that would perform well across diverse, resource-limited settings.

METHODS:

A cross-sectional study was conducted with 800 children aged 24 to 60 months across eight resource-limited settings. Parents were asked to respond to a household SES questionnaire, and the height of each child was measured. A statistical analysis was done in two phases. First, the best approach for selecting and weighting household assets as a proxy for wealth was identified. We compared four approaches to measuring wealth: maternal education, principal components analysis, Multidimensional Poverty Index, and a novel variable selection approach based on the use of random forests. Second, the selected wealth measure was combined with other relevant variables to form a more complete measure of household SES. We used child height-for-age Z-score (HAZ) as the outcome of interest.

RESULTS:

Mean age of study children was 41 months, 52% were boys, and 42% were stunted. Using cross-validation, we found that random forests yielded the lowest prediction error when selecting assets as a measure of household wealth. The final SES index included access to improved water and sanitation, eight selected assets, maternal education, and household income (the WAMI index). A 25% difference in the WAMI index was positively associated with a difference of 0.38 standard deviations in HAZ (95% CI 0.22 to 0.55).

CONCLUSIONS:

Statistical learning methods such as random forests provide an alternative to principal components analysis in the development of SES scores. Results from this multicountry study demonstrate the validity of a simplified SES index. With further validation, this simplified index may provide a standard approach for SES adjustment across resource-limited settings.

Chavez, M., Shams, N., Ellington, L., Naithani, N., Gilman, R., Steinhoff, M., Santosham, M., Black, R., Price, C., Gross, M., Checkley, W.

Respir Res. 2014 Apr 23

Abstract

BACKGROUND:

Guidelines do not currently recommend the use of lung ultrasound (LUS) as an alternative to chest X-ray (CXR) or chest computerized tomography (CT) scan for the diagnosis of pneumonia. We conducted a meta-analysis to summarize existing evidence of the diagnostic accuracy of LUS for pneumonia in adults.

METHODS:

We conducted a systematic search of published studies comparing the diagnostic accuracy of LUS against a referent CXR or chest CT scan and/or clinical criteria for pneumonia in adults aged ≥18 years. Eligible studies were required to have a CXR and/or chest CT scan at the time of evaluation. We manually extracted descriptive and quantitative information from eligible studies, and calculated pooled sensitivity and specificity using the Mantel-Haenszel method and pooled positive and negative likelihood ratios (LR) using the DerSimonian-Laird method. We assessed for heterogeneity using the Q and I2 statistics.

RESULTS:

Our initial search strategy yielded 2726 articles, of which 45 (1.7%) were manually selected for review and 10 (0.4%) were eligible for analyses. These 10 studies provided a combined sample size of 1172 participants. Six studies enrolled adult patients who were either hospitalized or admitted to Emergency Departments with suspicion of pneumonia and 4 studies enrolled critically-ill adult patients. LUS was performed by highly-skilled sonographers in seven studies, by trained physicians in two, and one did not mention level of training. All studies were conducted in high-income settings. LUS took a maximum of 13 minutes to conduct. Nine studies used a 3.5-5 MHz micro-convex transducer and one used a 5-9 MHz convex probe. Pooled sensitivity and specificity for the diagnosis of pneumonia using LUS were 94% (95% CI, 92%-96%) and 96% (94%-97%), respectively; pooled positive and negative LRs were 16.8 (7.7-37.0) and 0.07 (0.05-0.10), respectively; and, the area-under-the-ROC curve was 0.99 (0.98-0.99).

CONCLUSIONS:

Our meta-analysis supports that LUS, when conducted by highly-skilled sonographers, performs well for the diagnosis of pneumonia. General practitioners and Emergency Medicine physicians should be encouraged to learn LUS since it appears to be an established diagnostic tool in the hands of experienced physicians.

Bernabe-Ortiz, A., Diez-Canseco, F., Gilman, R., Cárdenas, M., Sacksteder, K., Miranda, J.

Trials. 2014 Mar 25;15:93

Abstract

BACKGROUND:

Controlling hypertension rates and maintaining normal blood pressure, particularly in resource-constrained settings, represent ongoing challenges of effective and affordable implementation in health care. One of the strategies being largely advocated to improve high blood pressure calls for salt reduction strategies. This study aims to estimate the impact of a population-level intervention based on sodium reduction and potassium increase – in practice, introducing a low-sodium, high-potassium salt substitute – on adult blood pressure levels.

METHODS/DESIGN:

The proposed implementation research study includes two components: Phase 1, an exploratory component, and Phase 2, an intervention component. The exploratory component involves a triangle taste test and a formative research study designed to gain an understanding of the best implementation methods. Phase 2 involves a pragmatic stepped wedge trial design where the intervention will be progressively implemented in several clusters starting the intervention randomly at different times. In addition, we will evaluate the implementation strategy using a cost-effectiveness analysis.

DISCUSSION:

This is the first project in a Latin-American setting to implement a salt substitution intervention at the population level to tackle high blood pressure. Data generated and lessons learnt from this study will provide a strong platform to address potential interventions applicable to other similar low- and middle-income settings.

Lee, G., Paredes, M., Rengifo, S., Ambikapathi, R., Peñataro, P., Kosek, M., Caulfield, LE.

Rev Panam Salud Publica. 2014 Sep;36(3)

OBJECTIVE:

To characterize feeding practices in a community in the Peruvian Amazon and to consider how this information could be used to strengthen programs and policies designed to improve nutrition and reduce child malnutrition in vulnerable communities.

METHODS:

Data from three structured questionnaires were combined to produce a comprehensive depiction of feeding in a sample of 246 infants from birth through 8 months of life in the community of Santa Clara de Nanay near Iquitos, Peru. Breastfeeding initiation practices, exclusive breastfeeding in the first 180 days of life, the introduction of solids, and complementary feeding practices from 6-8 months, were described and related to maternal, infant, and household characteristics, including food insecurity.

RESULTS:

The median duration of exclusive breastfeeding was 19 days. However, over the first 180 days of life, children were exclusively breastfed on 46.1% of days. Overall, 68.3% of infants received some semi-solid or solid food between 0-6 months and all had received semi-solids by the end of 8 months of age. The proportion of infants consuming a minimally acceptable (frequent and diverse) complementary diet was 2.9%, 7.9%, and 16.1% at 6, 7, and 8 months respectively.

CONCLUSIONS:

Although breastfeeding is nearly universal, promotion programs are needed in Santa Clara to 1) delay the introduction of plain water, other non-breast milk liquids, and semi-solid foods; 2) extend the period of exclusive breastfeeding; and 3) increase food diversity and the frequency of feeding during the period of complementary feeding. These results can be used to guide programs and policies to improve nutrition and reduce child malnutrition.