Background/Purpose: Magnesium plays an essential role in multiple cellular reactions, and there is increasing interest in its role in inflammation and pain. It has been estimated that nearly half the US population consumes less than the daily requirement of magnesium, likely due in part to decreased magnesium content in processed and refined foods and purified water. There are very few studies of the prevalence of hypomagnesemia in the general population, and no studies in a Rheumatology outpatient clinic population.  The purpose of this study was to determine the prevalence of hypomagnesemia in a VA Rheumatology outpatient clinic population, and explore its relationship to BMI, Type II diabetes, clinical disease measures, and potential contributing factors, including PPI use.

Methods: 100 consecutive new referrals to the Minneapolis VAMC Rheumatology clinic and 100 consecutive established inflammatory arthritis patients were included in the study.  Serum magnesium (Mg), ESR and CRP were measured, and BMI was recorded. Data regarding presence of Type 2 diabetes, rheumatoid arthritis (RA), renal function, alcohol, PPI, diuretic and vitamin supplement use was collected.  In new patients, self-reported pain scores (VAS) were recorded.  DAS28 scores were calculated in the subset of patients with newly diagnosed rheumatoid arthritis.  Chi-square and multivariable logistic regression analysis were used for statistical analysis.

Results: 76 of 200 patients (38%) had low serum magnesium levels (< 1.8 mg /dl). There was no significant difference between new vs established patients (41 % vs 35%, p= 0.38). Magnesium levels overall tended to be in the low normal range with an overall mean of 1.8 mg/dl ±0.25.  Mean Pain scores were slightly higher in the low magnesium group, but the difference was not significant (4.51 ±3.32 vs 3.76 ±2.87, p= 0.88). Mean values of ESR and CRP were not significantly different in the low vs normal Mg groups. Mean DAS28 scores were slightly higher in the RA patients with low Mg vs normal Mg (5.7±1.5 vs 3.9±1.9), however the number of patients was too small to draw statistical conclusions. Although a larger percentage of patients with low Mg were taking PPIs, the unadjusted effect of PPI use on prevalence of hypomagnesemia was small (OR 1.67, p=0.09). The concomitant use of diuretics did not significantly alter the risk. There was no significant association between reported alcohol or supplement use and hypomagnesemia. There was a weak association of BMI and hypomagnesemia (OR 1.05, p=0.04).  The strongest association was with T2DM, which was an independent risk factor for  hypomagnesemia (OR 3.77, p=0.001).

Conclusion: We found an alarmingly high prevalence of hypomagnesemia in a cohort of VA Rheumatology clinic outpatients. BMI and PPI use were weakly associated with hypomagnesemia. Hypomagnesemia may be associated with higher disease activity in rheumatoid arthritis. We found a strong association between T2 DM and hypomagnesemia. This study supports the need for future investigation of the prevalence and causes of hypomagnesemia in the rheumatic diseases, and its role in inflammation, pain and disease activity.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/high-prevalence-of-hypomagnesemia-and-its-relation-to-bmi-type-2-diabetes-and-clinical-disease-measures-in-a-va-outpatient-rheumatology-clinic-population/