Prevalence of Hypomagnesemia among Elderly Patients attending a Tertiary Care Center: A Descriptive Cross-sectional Study

ABSTRACT Introduction: Magnesium deficiency is common in the elderly and critically ill population and has been associated with a prolonged ICU stay. The knowledge of hypomagnesemia is essential as it could have prognostic and therapeutic implications in the elderly population. This study aimed to estimate the prevalence of hypomagnesemic in the elderly population visiting a tertiary care center. Methods: This descriptive cross-sectional study was conducted in a tertiary care hospital from March 21, 2020 to September 21, 2020. After obtaining ethical clearance from the institutional review committee (Ref. 2003202008), convenience sampling was done. Data were collected and entered in Microsoft Excel version 2007. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. Results: Out of 384 participants, 174 (45%) participants were found to have deranged magnesium levels, in which 111 (29%) (31.3-26.7 at 95% Confidence Interval) were found to be hypomagnesemia. Among them, 62 (29.4%) males and 49 (28.5%) females were hypomagnesemia. The average level of serum magnesium was 2.02±0.76 mg/dl ranging from 0.03 to 4.71. The mean age of participants was 70.31±8.13 years, among which the participants between the age group of 71-80 years presented with a maximum percentage of hypomagnesemia. Conclusions: The present study has shown that an apparently-healthy elderly population may have a magnesium deficiency that may need to be identified and treated for optimizing clinical care. Further multicentric studies with a greater sample size should be done in this field, which will benefit the elderly population.


INTRODUCTION
Magnesium is the second most common intracellular cation after potassium. It is highly controlled with a normal range of 1.8-2.6 mg/dl. 1 Its deficiency has been associated with several clinical manifestations such as arrhythmia, cardiac insufficiency, muscle weakness, and electrolyte imbalance. 2,3,4 It can also lead to increased intracellular sodium and calcium concentration and increased peripheral resistance and vasospasm. 5 Hypermagnesemia is rare, but hypomagnesemia, on the other hand, is more apparent in geriatric patients. 2 The probable association of hypomagnesemia with geriatric patients is due to low intake, diminished intestinal absorption, increased urinary output, and different drug interactions. 3,6 Clinically more attention is given to the electrolyte imbalance, but magnesium deficit is overlooked. But different studies have shown the importance of assessing magnesium levels in critically ill patients. 7 The objective of this study was to find the prevalence of hypomagnesemia among the elderly population. Written informed consent was obtained from all the study participants, and the data collection procedure was then carried out. Demographic data, including age and gender, were obtained on the proforma, and five ml of participant's blood was collected to examine the magnesium concentration in serum. Under the aseptic condition, a blood sample was obtained by venipuncture from the median cubital vein in a capped tube. Analysis of serum Magnesium was carried out using Xylidyl Blue colorimetric method utilizing Humalyzer Primus Version 3.2e semi auto analyzer in KMCTH laboratory, Duwakot.

METHODS
Data were entered in Microsoft excel 2007 version and transferred to Microsoft Excel Sheet for the required analysis. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. We counted the number of patients with hypomagnesemia (serum magnesium ≤1.8mg/dl). We classified them as mild (1.4-1.8mg/dl), moderate (1.0-1.39mg/dl), or severe (<1.0mg/dl) and compared within the groups. 2
Among the total study participants, 211 (55.1%) were males, and 172 (44.9%) were females. The mean age of the study participants was 70.31±8.13 years. According to their age, the participants were categorized into three groups, 60-70 years, 70-80 years, and above 80 years. The majority of the study participants, 205 (53.5%) were between 60-70 years while 129 (33.7%) were between 70-80 years and 49 (12.8%) were above 80 years. In the current study, the average serum magnesium level (mg/dl) was 2.02±0.76 ranging from 0.03 to 4.71.
The prevalence of hypomagnesemia among the study participants was 111 (29%). The prevalence of hypomagnesemia was higher in males 60 (29.4%) than in females 49 (28.5%). Among the study participants of different age groups, those of 81 years and above had the highest prevalence of hypomagnesemia 26 (53.1%), as shown in Table 1. Among the hypomagnesemic study participants, a majority had moderate hypomagnesemia (40.5%) ( Figure 1).

Figure 1. Distribution of hypomagnesemics according to the severity of hypomagnesemia
The majority of the males (41.9%) had moderate hypomagnesemia, whereas most females (42.8%) presented with severe hypomagnesemia (Figure 2).
JNMA I VOL 59 I ISSUE 233 I January 2021 Among the 60-70 years age group, the majority had moderate and severe hypomagnesemia 18 (37.5% each), and in the 71-80 years age group, the majority had severe hypomagnesemia 15 (40.6%). The prevalence of moderate hypomagnesemia was highest among the 81 years and above age group 16 (61.5%) (Figure 3).

DISCUSSION
The senior citizens' act 2063, Nepal defines senior citizens as people who are 60 years and above. Globally, the population of the elderly population is showing an increasing trend at 13% of the total population as of 2017. 8  A study done by Kumar et al. on patients above 60 years and admitted in ICU found that hypomagnesemia was associated with a slightly higher mortality rate. The requirement and duration of ventilator support were also higher, indicating that monitoring of serum Mg levels may have prognostic implications in the elderly. 3 Similar study done by Martin et al. also found 10.7% of the total population (1576) had a serum magnesium level below 0.7mmol/l, with 4.4% having a serum level less than 0.65mmol/l. 11 Davidovic et al. have suggested that Mg therapy can be performed within supplementation, and those doses are completely safe. In geriatric patients, the main importance is Mg's cytoprotective role, which could theoretically extend years of living. 6 But, in Nepal, such studies are rare if not absent, as suggested by our literature search, highlighting the need for more research in this area.
In our study, in the age group 71-80 years, 37 (28.7%) were hypomagnesemic. Similarly, in the 81 and above age group, 26 (53%) were hypomagnesemic. This finding is greater than that of the cohort study done by Nasser et al., where they have taken 75 years and above study population, among which 6% had hypomagnesemia. The study has also reported that hypomagnesemia was associated with a higher 30-day mortality rate (18.4%) compared to normomagnesemic group (14.8%). 4 In a study done by Arinzone, et al., hypomagnesemia was found in 36% of the patients, of whom 35% presented with moderate HM (0.8-0.9 microequiv./l) and 18% with severe HM (<or=0.7 microequiv./l). In their study, the sample population is above 65 years, like ours. 12  The study's limitation was that it is a single institution study, and the sample size isn't effective in formulating a consensus. The inclusion of critically ill patients could also have helped to broaden the understanding of the importance of hypomagnesemia in critical care settings.

CONCLUSIONS
The present study has shown that an apparentlyhealthy elderly population may have Magnesium deficiency that may need to be identified and treated, optimizing clinical care. Although the prevalence of hypomagnesemia is high among males, the female population presented with a higher prevalence of severe hypomagnesemia. The higher prevalence of severe hypomagnesemia in the 71-80 years age group is an important finding that needs further exploration and clinical judgment while managing this population. Further multicentric studies with a greater sample size should be done in this field, which will benefit the elderly population.