Desalinated seawater supply and all-cause mortality in hospitalized acute myocardial infarction patients from the Acute Coronary Syndrome Israeli Survey 2002–2013

Background Consuming desalinated seawater (DSW) as drinking water (DW) may reduce magnesium in water intake causing hypomagnesemia and adverse cardiovascular effects. Methods We evaluated 30-day and 1-year all-cause mortality of acute myocardial infarction (AMI) patients enrolled in the biannual Acute Coronary Syndrome Israeli Survey (ACSIS) during 2002–2013. Patients (n = 4678) were divided into 2 groups: those living in regions supplied by DSW (n = 1600, 34.2%) and non-DSW (n = 3078, 65.8%). Data were compared between an early period [2002–2006 surveys (n = 2531) — before desalination] and a late period [2008–2013 surveys (n = 2147) — during desalination]. Results Thirty-day all-cause-mortality was significantly higher in the late period in patients from the DSW regions compared with those from the non-DSW regions (HR = 2.35 CI 95% 1.33–4.15, P < 0.001) while in the early period there was no significant difference (HR = 1.37 CI 95% 0.9–2, P = 0.14). Likewise, there was a significantly higher 1-year all-cause mortality in the late period in patients from DSW regions compared with those from the non-DSW regions (HR = 1.87 CI 95% 1.32–2.63, P < 0.0001), while in the early period there was no significant difference (HR = 1.17 CI 95% 0.9–1.5, P = 0.22). Admission serum magnesium level (M ± SD) in the DSW regions (n = 130) was 1.94 ± 0.24 mg/dL compared with 2.08 ± 0.27 mg/dL in 81 patients in the non-DSW (P < 0.0001). Conclusions Higher 30-day and 1-year all-cause mortality in AMI patients, found in the DSW regions may be attributed to reduced magnesium intake secondary to DSW consumption.