Vitamin B12 deficiency among adult diabetic patients in Uganda: relation to glycaemic control and haemoglobin concentration

Glycaemic control among type 2 diabetes patients in sub-Saharan Africa from 2012 to 2022: a systematic review and meta-analysis

BACKGROUND

There is an increased burden of diabetes globally including in sub-Saharan Africa. The literature shows that glycaemic control among type 2 diabetes patients is poor in most countries in sub-Saharan Africa. Understanding the factors influencing glycaemic control in this region is therefore important to develop interventions to optimize glycaemic control. We carried out a systematic review to determine the prevalence and factors associated with glycaemic control in sub-Saharan Africa to inform the development of a glycaemic control framework in the Democratic Republic of the Congo.

METHODS

We searched five databases (African Index Medicus, Africa-Wide Information, Global Health, PubMed, and Web of Science) using the following search terms: type-2 diabetes, glycaemic control, and sub-Saharan Africa. Only peer-reviewed articles from January 2012 to May 2022 were eligible for this review. Two reviewers, independently, selected articles, assessed their methodological quality using Joanna Briggs checklists, and extracted data. A meta-analysis was performed to estimate the prevalence of glycaemic control. Factors associated with glycaemic control were presented as a narrative synthesis due to heterogeneity as assessed by the I2.

RESULTS

A total of 74 studies, involving 21,133 participants were included in the review. The pooled prevalence of good glycaemic control was 30% (95% CI:27.6-32.9). The glycaemic control prevalence ranged from 10-60%. Younger and older age, gender, lower income, absence of health insurance, low level of education, place of residence, family history of diabetes, longer duration of diabetes, pill burden, treatment regimen, side effects, use of statins or antihypertensives, alcohol consumption, smoking, presence of comorbidities/complications, and poor management were associated with poor glycaemic control. On the other hand, positive perceived family support, adequate coping strategies, high diabetes health literacy, dietary adherence, exercise practice, attendance to follow-up, and medication adherence were associated with good glycaemic control.

CONCLUSION

Suboptimal glycaemic control is pervasive among patients with type-2 diabetes in sub-Saharan Africa and poses a significant public health challenge. While urgent interventions are required to optimize glycaemic control in this region, these should consider sociodemographic, lifestyle, clinical, and treatment-related factors. This systematic review and meta-analysis protocol is registered in PROSPERO under CRD 42021237941.

Evaluating the correlation between serum vitamin B12 levels and various haematologic indices among metformin-treated type 2 diabetic patients: A prospective analytical study

Background:

Metformin-induced vitamin B12 deficiency state or metformin-induced hypocobalaminemia is gradually becoming an epidemic among diabetic patients on moderate-to-high doses of metformin or those diabetic patients on metformin for a long period of time. The potential effect of chronic metformin pharmacotherapy to cause vitamin B12 deficiency with abnormalities in haematologic indices and central/peripheral neuropathy has been widely reported. Long-term usage of metformin has been reported to be associated with intestinal malabsorption of vitamin B12 culminating in vitamin B12 deficiency with likely associated haematologic abnormalities (including macro-ovalocytic anaemia and immune dysfunctioning due to hypersegmentation of polymorphonuclear leukocytes), central/peripheral neuropathy and manifestation of biochemical derangements such as elevated homocysteine and methyl malonate levels.

Aim:

This study aimed to determine the correlation between serum vitamin B12 levels and various haematologic indices among metformin-treated type 2 diabetic patients in a clinical practice setting with the rational purpose of alleviating/preventing the associated derangements.

Materials and Methods:

This was a case-control, prospective, analytical, observational study of 200 adult participants (100 per group) attending the Endocrinology Out-patients Clinic of Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria. For each participant, serum vitamin B12 level was determined using a vitamin B12 immunoassay technique, while the corresponding complete blood count was done using PCE-210N autohaematology analyser. Data were presented using tables and figures. Chi-square test was used to compare categorical variables, Student t-test was used in comparing means of continuous variables, while Pearson’s correlation study was done to determine the existence of any statistically significant correlation(s) between the serum vitamin B12 levels and various haematologic indices among the participants.

Results:

Approximately 41% versus 20% of the metformin-treated and metformin-naive diabetic patients, respectively, had frank vitamin B12 deficiency. There was a statistical difference between the total serum vitamin B12 levels in male and female diabetic patients with p = 0.048. Also, statistically significant differences existed with respect to mean corpuscular volume (MCV), mean corpuscular haemoglobin and total white blood cells count among the metformin-treated and metformin-naive diabetic patients. Furthermore, a statistically significant weak positive correlation existed between pack cell volume (PCV) and serum vitamin B12 level ( r = +0.148, p = 0.037), but a statistically significant weak negative correlation existed between MCV and serum vitamin B12 level ( r = −0.245, p = 0.0001). In addition, the test for associations between the serum vitamin B12 categorization status or metformin exposure status and the peripheral neuropathy components assessment revealed that there were statistically significant associations between the serum vitamin B12 categorization status or metformin exposure status versus pain sense ( p < 0.0001 or <0.001), vibration sense ( p < 0.0001 or <0.001) and light touch sense ( p < 0.0001 or <0.001) among the participants.

Conclusion:

In this study, statistically significant weak positive and weak negative correlations existed between serum vitamin B12 level versus PCV, and serum vitamin B12 level versus MCV, respectively. The peripheral neuropathy components assessment revealed that there were statistically significant associations between the serum vitamin B12 categorization status or metformin exposure status versus pain sense, vibration sense and light touch sense among the participants.

Prevalence of vitamin B12 deficiency in South Indians with different grades of glucose tolerance

AIMS

To determine the prevalence of vitamin B₁₂ deficiency in an urban south Indian population in individuals with different grades of glucose tolerance.

METHODS

A total of 1500 individuals [900 normal glucose tolerance (NGT), 300 prediabetes and 300 type 2 diabetes (T2DM)] who were not on vitamin B₁₂ supplementation were randomly selected from the Chennai Urban Rural Epidemiological Study (CURES) follow-up study. Anthropometric, clinical and biochemical investigations, which included vitamin B₁₂, insulin, homocysteine, HbA1c and serum lipids, were measured. Vitamin B₁₂ ≤ 191 pg/ml was defined as absolute vitamin B₁₂ deficiency and vitamin B₁₂ > 191 pg/ml and ≤ 350 pg/ml as borderline deficiency.

RESULTS

The mean levels of vitamin B₁₂ significantly decreased with increasing degrees of glucose tolerance (NGT 444 ± 368; prediabetes 409 ± 246; T2DM 389 ± 211 pg/ml, p = 0.021). The prevalence of absolute vitamin B₁₂ deficiency was 14.9% while 37.6% had borderline deficiency. The prevalence of absolute vitamin B₁₂ deficiency was significantly higher among individuals with T2DM (18.7%) followed by prediabetes (15%) and NGT(13.7%) [p for trend = 0.05]. The prevalence of vitamin B₁₂ significantly increased with age (p < 0.05) and in those with abdominal obesity (p < 0.001). Men and vegetarians had twice the risk of vitamin B₁₂ deficiency compared to women and non-vegetarians, respectively. Among individuals with NGT, prediabetes and T2DM, vitamin B₁₂ negatively correlated with homocysteine.

CONCLUSION

This study reports that the levels of vitamin B₁₂ decreased with increasing severity of glucose tolerance.

Dyslipidaemia in a Black African diabetic population: burden, pattern and predictors

Objectives

This study sought to assess the burden, pattern and predictors of dyslipidaemia in 425 adult diabetic patients in Uganda.

Results

The median (IQR) age of the study participants was 53 (43.5–62) years with a female majority (283, 66.9%). Dyslipidaemia defined as presence of ≥ 1 lipid abnormalities was observed in 374 (88%) study participants. Collectively, the predictors of dyslipidaemia were: female gender, study site (private hospitals), type of diabetes (type 2 diabetes mellitus), statin therapy, increased body mass index and diastolic blood pressure. Proactive screening of dyslipidaemia and its optimal management using lipid lowering therapy should be emphasised among adult diabetic patients in Uganda.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-2916-y) contains supplementary material, which is available to authorized users.