Neurological Conditions: estimating the prevalence in Scotland of selected conditions using GP and Hospital Admissions datasets

Scottish Primary Care Information Resource (SPIRE) via PHS

Scottish Burden of Disease Study team (PHS) – Scottish Morbidity Records (SMR) data

Data extract drew on records for 72.7% of registered patients

Data estimates drew on records for all people admitted to hospital over the specified 20 year period.

Read codes

ICD-10 codes

Mapping of Read codes to ICD-10 codes: for some conditions ICD codes might have over-counted.

For a few conditions no suitable Read codes were identified and so data could not be extracted (see Annex C).

For a few conditions no suitable Read codes were identified and so they could not be mapped across to ICD codes.

Estimates were not possible for a small number of conditions for which SPIRE data were provided (see Annex C).

Snapshot of patients on a specific day with a diagnosis 'ever recorded'.

Coding – any time.

Records date back to the 1940s

Patients coded at any time over a 20-year timeframe up to 31 December 2019.

This approach does not take account of any patients who recovered from their diagnosed condition.

General practice recording of patient diagnoses

Hospital coding of patient admissions

General practice recorded data are dependent on good computerised Read coding by general practices.

Hospital admissions-generated estimates could under-count population prevalence for some conditions where hospital admission is not routine.

General practice data represent prevalence as recorded among GP- registered patients.

Hospital Admissions data represent prevalence as recorded among people admitted to hospital in the specified timeframe.

Hospital outpatients data are not available because of coding / recording issues.

Not known how many registered patients died recently and whose death is not yet recorded in their general practice clinical systems. There is no established approach to estimate this.

Link to National Records of Scotland (NRS) mortality data enabled exclusion of people who had died since their diagnosis.

General practice recorded dataset only includes data for currently registered patients (i.e. it excludes patients who were diagnosed in Scotland but have since migrated elsewhere).

A linkage to the national Community Health Index (CHI) register was undertaken to exclude patients who were no longer resident in Scotland as at 31 December 2019.