Table 1.
Frequency of registered diagnosis code for different previously suggested risk factor disorders and pregnancy exposure.
| Registered diagnosis code one year prior to index date (ICD-10 code) | IIH N:902 n (%) |
GP controls N: 4510 n (%) |
Obese controls N:4510 n (%) |
|---|---|---|---|
| Addison (E27) | <4 (≤0.3) | <4 (<0.1) | <4 (<0.1) |
| Arterial hypertension (I10-15) | 72 (8.0) | 23 (0.5) | 91 (2.0) |
| Coagulopathy (D65-68) | 6 (0.7) | <4 (<0.1) | 9 (0.2) |
| Cushing (E24) | <4 (≤0.3) | <4 (<0.1) | <4 (<0.1) |
| Hyperparathyroidism (E21) | <4 (≤0.3) | <4 (<0.1) | <4 (<0.1) |
| Hyperthyroidism (E05) | <4 (≤0.3) | 8 (0.2) | 12 (0.3) |
| Iron deficiency anaemia (D50) | 9 (1.0) | 5 (0.1) | 10 (0.2) |
| Kidney failure (N17-19) | 11 (1.2) | 4 (0.1) | 5 (0.1) |
| Ovary dysfunction incl PCOS in females (E28) | 12 (1.6) | 9 (0.2) | 39 (1.0) |
| Pregnancy exposure in females (pregnancy register data) | 56 (7) | 262 (7) | 272 (7) |
| Sarcoidosis (D86) | <4 (≤0.3) | <4 (<0.1) | 7 (0.2) |
| SLE (M32) | 11 (1.2) | 4 (0.1) | 6 (0.1) |
| Turner’s and Down’s syndrome (Q96+Q90) | <4 (≤0.3) | <4 (<0.1) | 5 (0.1) |
| Sensitivity analysis | |||
| Benign skin tumors (D22-23) | 11 (1.2) | 33 (0.7) | 36 (0.8) |
IIH = idiopathic intracranial hypertension, GP = general population, PCOS = polycystic ovary syndrome, SLE= systemic lupus erythematosus. Used ICD-10 codes in brackets.