Validating epilepsy diagnoses in routinely collected data.

PURPOSE: Anonymised, routinely-collected healthcare data is increasingly being used for epilepsy research. We validated algorithms using general practitioner (GP) primary healthcare records to identify people with epilepsy from anonymised healthcare data within the Secure Anonymised Information Linkage (SAIL) databank in Wales, UK. METHOD: A reference population of 150 people with definite epilepsy and 150 people without epilepsy was ascertained from hospital records and linked to records contained within SAIL (containing GP records for 2.4 million people). We used three different algorithms, using combinations of GP epilepsy diagnosis and anti-epileptic drug (AED) prescription codes, to identify the reference population. RESULTS: Combining diagnosis and AED prescription codes had a sensitivity of 84% (95% ci 77-90) and specificity of 98% (95-100) in identifying people with epilepsy; diagnosis codes alone had a sensitivity of 86% (80-91) and a specificity of 97% (92-99); and AED prescription codes alone achieved a sensitivity of 92% (70-83) and a specificity of 73% (65-80). Using AED codes only was more accurate in children achieving a sensitivity of 88% (75-95) and specificity of 98% (88-100). CONCLUSION: GP epilepsy diagnosis and AED prescription codes can be confidently used to identify people with epilepsy using anonymised healthcare records in Wales, UK.

Pseudotumor cerebri syndrome in childhood: incidence, clinical profile and risk factors in a national prospective population-based cohort study.

AIM: To investigate the epidemiology, clinical profile and risk factors of pseudotumor cerebri syndrome (PTCS) in children aged 1-16 years. METHODS: A national prospective population-based cohort study over 25 months. Newly diagnosed PTCS cases notified via British Paediatric Surveillance Unit were ascertained using classical diagnostic criteria and categorised according to 2013 revised diagnostic criteria. We derived national age, sex and weight-specific annual incidence rates and assessed effects of sex and weight categories. RESULTS: We identified 185 PTCS cases of which 166 also fulfilled revised diagnostic criteria. The national annual incidence (95% CI) of PTCS in children aged 1-16 years was 0.71 (0.57 to 0.87) per 100 000 population increasing with age and weight to 4.18 and 10.7 per 100 000 in obese boys and girls aged 12-15 years, respectively. Incidence rates under 7 years were similar in both sexes. From 7 years onwards, the incidence in girls was double that in boys, but only in overweight (including obese) children. In children aged 12-15 years, an estimated 82% of the incidence of PTCS was attributable to obesity. Two subgroups of PTCS were apparent: 168 (91%) cases aged from 7 years frequently presented on medication and with headache and were predominantly female and obese. The remaining 17 (9%) cases under 7 years often lacked these risk factors and commonly presented with paralytic squint. CONCLUSIONS: This uniquely large population-based study of childhood PTCS will inform the design of future intervention studies. It suggests that weight reduction is central to the prevention of PTCS.