Effect of the inclusion of mobile phone interviews to Vigitel

Abstract

OBJECTIVE To evaluate the impact on the prevalence changes of risk factors for chronic diseases, published in the Surveillance System of Risk and Protection Factors for Chronic Diseases by Telephone Survey (Vigitel), after the inclusion of data from the population only with mobile phone.METHODS Our study used data from the 26 State capitals and Federal District of Brazil obtained by the National Survey on Health (PNS) and Vigitel, both held in 2013. In each capital, we added a subsample of 200 adults living in households with only mobile phones, extracted from PNS, to the Vigitel 2013 database, with approximately 1,900 households, named Vigitel dual frame.RESULTS Vigitel results showed absolute relative biases between 0.18% and 14.85%. The system underestimated the frequency of adult smokers (10.77%), whole milk consumption (52.82%), and soft drink consumption (22.22%). Additionally, it overestimated the prevalence of hypertension (25.46%). In the simulations using Vigitel dual frame, with inclusion of the sample of adults living in households with only mobile phones, the bias of estimates was reduced in five out of eight analyzed indicators, with greater effects in regions with lower rates of landline coverage. In comparing regions, we observed negative correlation (ρ = −0.91) between the percentage of indicators with presence of bias and the percentage of households with only mobile phone.CONCLUSIONS The results of this study indicate the benefits of including a subsample of 200 adults with only mobile phone on the Vigitel sample, especially in the capitals of the North and Northeast regions.

The variation of the burden of hypertension and diabetes in two large districts of the city of São Paulo, Brazil, based on primary health care routinely-collected data

“…Only 61% of households in Brazil have a landline telephone, with a heterogeneous distribution among cities [ 27 ], and as a result VIGITEL is known to overestimate the prevalence of hypertension [ 27 , 28 ]. This is in accordance with the lower prevalence of hypertension found among the entire study population, when compared to the survey estimates to São Paulo, what could have been further influenced by the fact that the study used diagnoses of hypertension established by a physician, while VIGITEL used self-reported diagnoses.…”

A Telephone Surveillance System for Noncommunicable Diseases in Brazil

“…In Brazil, a 2008 pilot study 25 and a 2017 simulation study assessed the feasibility of including cell phone interviews in surveys. 19 Although these studies indicated the benefits of including a subsample of adults with only mobile phones in the VIGITEL sample, especially in the capitals of the northern and northeastern regions, it is not known whether cell phones will be included in the sample.…”

“…In contrast, in the southern and southeastern regions, which have high rates of landline use, the biases may be negligible. 19 Data originating from the population residing only in state capitals are also limited because lifestyles vary widely from capitals to smaller municipalities, especially the behavioral risk factors for NCDs.…”

“…24 The exclusive use of cell phones is especially high in younger age groups and in certain racial/ethnic minority groups. 23 Including cell phone numbers is even more necessary where landline coverage is limited, as in the northern and northeastern regions, 19 because of differences in the characteristics of persons living in households with or without landline telephones.…”

Population-based surveys and monitoring of noncommunicable diseases

“…Post-stratification weights are used to correct estimates 5 . Of both articles presented in this supplement based on analysis of information collected on VIGITEL 2015, the study by Bernal et al 18 aimed to assess the impact on the changes of the prevalence of chronic diseases’ risk factors, disclosed on Vigitel, after the inclusion of data from the population that does not have fixed telephone line, only mobile phone. The other article analyzed the factors associated with the self-reported diagnosis of arterial hypertension 19 .…”