Variable | Definition |
---|---|
Index date | Date of surgery |
Index year | Year of surgery |
Use of anti-epileptics (AED) | Purchase of ATC class N03A (anti-epileptics), except those mainly used for pain: N03AX12 (Gabapentin) and N03AX16 (Pregabalin), within the last 90 days. |
History of seizure/epilepsy | Purchase of ATC class N03A (anti-epileptics), except N03AX12 and N03AX16 and/or ICD-10: G40 (epilepsy) and/or registered “seizure” as symptom in SBTR. All within one year prior to index date. |
Use of antidepressants | Purchase of ATC: N06A (antidepressants) within the last 90 days. |
History of depression | ATC: N06A and/or ICD-10: F20.4 (post-schizophrenic depression), F31.3-F31.5 (bipolar affective disorder), F32 (depressive episode), F33.0-F33.3 (recurrent depressive disorder), F34 (persistent mood disorders), F41.2 (mixed anxiety and depressive disorder), F43.2 (adjustment disorders). All within one year prior to index date. |
Use of sedatives | Purchase of ATC: N05B (anxiolytics) and N05C (hypnotics and sedatives) within the last 30 days. |
History of anxiety and/or sleeping difficulties | ATC: N05B and/or N05C (except N05CD08) and/or ICD-10: G47 (sleeping disorders), F40 (phobias), F41.0 (anxiety disorders), F41.1, F41.3, F41.8, F41.9, F42.0 (obsessive disorders), F42.1, F42.2, F42.8, F42.9. All within one year prior to index date. |
Elixhauser comorbidity index | According to index. The conditions removed from the index due to possible association with diagnosis of LGG were: G40, G41 (Status epilepticus), R56 (Convulsions), R47 (Dysphasia/aphasia), C70–72 (Malignant tumour in central nervous system). Cases and controls were provided with a score from 0 to 30 based upon comorbid categories present or not. We report categories as 0, 1, 2, ≥3. The ICD-10 data used to classify comorbidity was taken from the NPR during the year prior to index date. |