MMP1 and subarachnoid hemorrhage: However, in a multivariate analysis where the patients’ age, sex, family history of ICAs or subarachnoid hemorrhage (SAH), renal function (serum creatinine level), dialysis therapy and MMP1 levels were taken into account as potential confounding factors, the serum MMP1 level was confirmed to be one of the risk factors associated with ICAs formation in ADPKD patients (adjusted odds ratio (95% CI); 1.891 (1.139–3.138); P = 0.014; Table 2).