Serum Magnesium Level and Acute Exacerbation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a life-threatening lung disease and the third leading cause of death globally. Magnesium (Mg2+) is an intracellular cation that regulates the bronchial tone and respiratory muscle function. Consequently, Mg2+ deficiency can lead to exacerbations of pulmonary diseases as it helps in alleviating bronchospasm.[1] Magnesium deficiency also triggers a low-grade inflammatory state.[1] Hypomagnesemia, or low magnesium, is a common finding during COPD exacerbations and can be correlated with longer hospital stays, a higher risk of increased exacerbations, and more advanced disease stages. Magnesium plays a role in bronchodilation, airway muscle function, and anti-inflammatory action, which may explain its protective effect in chronic respiratory diseases.[2] Stages 2 and 3 of COPD are usually associated with hypoxemia, which, when combined with chronic respiratory insufficiency, can cause hypomagnesemia and magnesium depletion.[3] Among all cases diagnosed with acute exacerbation of COPD, most of the patients with hypomagnesemia had stage 2 and stage 3 disease, and few were in stage 4. Patients with serum Mg2+ <1.7 mg/dL had a greater number of acute exacerbations as compared to patients with serum Mg2+ >1.7 mg/dL. Frequent exacerbations are usually associated with low forced expiratory volume in one second (FEV1).[4] The increased number of exacerbations noticed in patients with serum Mg2+ <1.7 mg/dL could be due to raised systemic airway inflammation, and another possible reason could be due to increased sputum eosinophils in response to bacterial and viral infection.[5] The article, “Association of serum magnesium level with frequency of acute exacerbations in chronic obstructive pulmonary disease patients: A prospective observational study,” published in this issue of the journal by Yasmin Khan et al., aims to establish an association of serum magnesium level with frequency of AECOPD.[6] This article is interesting as the study points out a new marker for COPD EXACERBATION and needs further studies to understand whether correcting this variable would reduce further exacerbations. The article mainly discusses the number of COPD patients of >40 years getting admitted in a tertiary hospital with exacerbation, and they are grouped into patients with exacerbation frequency less than two episodes and more than three episodes. Age, body mass index, FEV1, forced vital capacity (FVC), serum protein, and serum magnesium levels were monitored during admissions and during a 3-month follow-up period of 1 year. Results showed that Serum Mg was significantly higher in the AECOPD ≤2 group than AECOPD ≥3 group. Mean FVC and mean FEV1 were significantly higher in the lesser exacerbation group than in the higher exacerbation group. This study showed that age, body mass index, FEV1, FVC, and serum Mg were inversely linked to exacerbations. Lower age group patients with COPD showed a higher frequency of exacerbations. Even though the study highlights an important reversible factor for COPD exacerbations, because of the small sample size, the findings should be validated by further studies involving a larger sample size. All the confounding factors altering the magnesium levels are not taken into consideration in this study. Further to that, many of the patients would be getting antibiotics, and this significantly alters magnesium levels. The article raises an important question that, considering the association of serum magnesium levels with the number of COPD exacerbations, magnesium deficiency, if detected early and corrected, would alter the morbidity and mortality in favour of COPD patients, which is a promising scope for future studies.