TY - JOUR T1 - Decreasing incidence of adenotonsillar problems in Dutch general practice: real or artefact? JF - British Journal of General Practice JO - Br J Gen Pract SP - e368 LP - e375 DO - 10.3399/bjgp09X473141 VL - 59 IS - 569 AU - Marion CJ Biermans AU - Ellen HM Theuns-Lamers AU - Peter Spreeuwenberg AU - Robert A Verheij AU - Johannes C van der Wouden AU - Pieter F de Vries Robbé AU - Gerhard A Zielhuis Y1 - 2009/12/01 UR - http://bjgp.org/content/59/569/e368.abstract N2 - Background The incidence of hypertrophy and recurrent infections of the tonsils/adenoids appears to be decreasing in the Netherlands. It is uncertain whether this is a ‘real’ decrease in the incidence of disease or an ‘artefact’.Aim To investigate possible causes of the decreasing incidence of adenotonsillar problems among Dutch children.Design of study Observational.Setting A nationally representative general practice database.Method Incidence rates were calculated over 2002–2005 among children aged 0–14 years. Multilevel Poisson regression analyses were used to examine the following possible causes of changing incidence rates: change in recording (more substitution codes), change in the demand for care (fewer visits to the GP), and change in the supply of care (fewer antibiotic prescriptions and referrals). Indications for a ‘real’ change in the incidence of disease were examined by calculating incidence rates of other clinical manifestations of microbial pathogens that may cause adenotonsillar problems.Results The incidence rate decreased significantly (P = 0.017) from 3.0 to 1.3 per 1000 children per year. Correcting for demand for and supply of care led to a smaller decline in yearly incidence, from 2.9 to 1.7 per 1000 children per year (P = 0.105). No clearly similar trend was found in other clinical manifestations of viruses and bacteria that may cause adenotonsillar problems.Conclusion Part of the declining trend can be explained by a change in the demand for and supply of care, but no apparent causal clue emerged for the residual declining trend in the incidence of disease. ER -