Extrapolating respiratory tract infection incidences to a rural area of Ghana using a probability model for hospital attendance

SummaryObjectiveThe aim of the current study was to extrapolate incidences for respiratory tract infections (RTI) using referral data from a local hospital in Ghana weighted by the individual likelihood of a hospital visit.MethodsDiagnoses from children visiting a rural hospital in Ghana during August 2007 to September 2008 were recorded. A logistic regression model, based on a population study conducted within the hospital catchment area, was used to calculate the individual probability of clinic attendance and to extrapolate the number of recorded cases. Cumulative incidences for children living in the hospital catchment area were estimated.ResultsUpper RTI was the most common respiratory diagnosis, with an extrapolated incidence of 17 481 cases per 100 000 per year, followed by pneumonia with an incidence of 2496 per 100 000 per year. All diseases analyzed were most common in the first year of life.ConclusionsIn general the study results are in line with comparable studies. Several methodological issues biasing the results in different directions were identified. For example, opportunistic infections that are more often observed in hospital attendees are likely to be overestimated. However, the applied approach presents a tool for areas where disease monitoring systems are not established.