Secondary causes of erythrocytosis, stratified by presence of JAK2 mutation
| Cause* | No. of patients | p value | |
|---|---|---|---|
| Positive for JAK2 mutation n = 106 | Negative for JAK2 mutation n = 785 | ||
| Smoking | 25 (23.6) | 319 (40.6) | < 0.001 |
| OSA | 6 (5.7) | 251 (32.0) | < 0.001 |
| COPD | 5 (4.7) | 107 (13.6) | 0.007 |
| Other hypoxic lung diseases | 6 (5.7) | 83 (10.6) | 0.12 |
| SGLT2 inhibitors | 2 (1.9) | 95 (12.1) | < 0.001 |
| Testosterone use | 1 (0.9) | 73 (9.3) | 0.001 |
| EPO-secreting tumour | 0 (0.0) | 5 (0.6) | 1.0 |
Note: COPD = chronic obstructive pulmonary disease, EPO = erythropoietin, OSA = obstructive sleep apnea, SGLT2 = sodium–glucose cotransporter-2.
↵* Patients may have more than 1 secondary cause.