Establishment of reference interval for hemoglobin A1C and other hemoglobin subfractions for healthy Saudi adults

BACKGROUND

The establishment of Reference Intervals (RIs) for Hemoglobin A1C and other hemoglobin subfractions (A1A, A1B, F, LA1C, A0) is of utmost importance in screening, diagnosing, and monitoring diabetes and other hemoglobin abnormalities through the application of high-pressure liquid chromatography (HPLC) technique. Because there are no locally established RIs for these parameters, it is essential to establish RIs specific to the Saudi population to accurately diagnose and monitor diabetic individuals and identify abnormal levels in hemoglobin subfractions.

METHODS

As part of the IFCC global multicenter study of laboratory reference values, a cross-sectional study was conducted in Saudi Arabia. The study involved recruiting a total of 381 healthy adult subjects (>18 years, BMI 28.3 ± 6 kg/m2). Blood samples were analyzed for A1C, biochemical and other immunoassay parameters. The need for RIs based on sex, age, and BMI was determined using the standard deviation ratio (SDR) through a 3-level nested ANOVA.

RESULTS

Based on the threshold of SDR≥0.4, RIs for A1C and other Hb subfractions were not partitioned by sex or BMI, but partitioned by age (<45 & ≥45 years) for A1C, LA1C, A0 and F. Spearman's correlation between glucose, insulin, and C-peptide showed a positive association with different hemoglobin subtractions of A1B, F, A1C, and LA1C. The RIs were obtained by using the parametric method and the latent abnormal values exclusion (LAVE) principle was applied on A1C.

CONCLUSION

This study established RIs for A1C and other Hb subfractions for healthy adult Saudis. Age was found to be an important source of variation for most of the parameters including A1C. These findings will enhance the understanding and clinical decision-making concerning A1C and other hemoglobin subfractions. The elevated upper limit of RIs for A1C reflects the high prevalence of diabetes in the Saudi population specially in those with increased age.

The impact of the implementation of computerized insulin order sets for the control of hyperglycemia in hospitalized cardiac patients

Background

Glycemic control is crucial in managing hospitalized patients with type II diabetes (T2DM), and it presents as a clinical challenge in the cardiac population. Therefore, we aimed to evaluate the impact of computerized insulin order sets in T2DM hospitalized cardiac patients.

Methods

A quasi-experimental, pre- and post-study design. We included T2DM patients who were hospitalized for at least 3 days. Patients undergoing cardiac surgery were excluded. The primary endpoint was the mean difference in random blood glucose level (BGL) before and after the implementation of insulin order sets. While the secondary endpoints were to compare the median differences in fasting BGLs and the number of hyperglycemic and hypoglycemic episodes during the first 7 days. The study consisted of three phases: pre-implementation, intervention and post-phase. In the intervention phase, insulin order sets were integrated into the electronic prescribing system, and education was provided to the cardiology department. The post-phase included the patient's post-implementations.

Results

A total of 194 patients were enrolled during the study period. The mean random BGL was 11.17 mmol/L, 95% CI, 10.6-11.7 in the pre-phase and 9.5 mmol/L, 95% CI, 9-1 -9.9 mmol/L in the post-phase (P < 0.001). The median fasting BGL was 9.2 mmol/L (7.4-11.8, IQR) in the pre-phase and 8.5 mmol/L (6.6-10.3, IQR) in the post-phase (P = 0.027). The number of hypoglycemic episodes was 24 in pre-phase and 33 in post-phase (P = 0.13).

Conclusion

The use of computerized insulin order sets was associated with potential improvements in random and fasting glycemic control without increasing the risk of hyperglycemia or hypoglycemia.

The Effect of PCSK9 Inhibitors on LDL-C Target Achievement in Patients with Homozygous Familial Hypercholesterolemia: A Retrospective Cohort Analysis

INTRODUCTION

Achieving target low-density lipoprotein-cholesterol (LDL-C) levels remains challenging when treating homozygous familial hypercholesterolemia (HoFH). Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) are prescribed in addition to statins and ezetimibe, but patients' response varies and depends on residual low-density lipoprotein receptor (LDLR) function.

METHODS

A multicenter, retrospective observational analysis evaluated LDL-C target achievement in response to PCSK9i treatment in 28 patients with HoFH from the Middle East/North Africa region. Effect of genotype was investigated. Demographic and clinical information was retrospectively obtained from medical records. Patient response to PCSK9i treatment was assessed by calculating percentage changes in lipid levels from pre-PCSK9i treatment baseline to most recent follow-up visit where patients were recorded as receiving PCSK9i on top of standard of care lipid-lowering therapies (LLTs; i.e., statins/ezetimibe) and assessing European Atherosclerosis Society (EAS) target achievement up to January 31, 2022. Lowest LDL-C level while receiving PCSK9i was identified.

RESULTS

The cohort (n = 28) had a mean age (standard deviation; SD) of 22.8 (9.8) years (n = 28) and was 51% female (n = 27). Baseline LDL-C data were available in 24/28 (85.7%) patients (mean [SD] 14.0 [3.0] mmol/L). Median (interquartile range) duration of PCSK9i treatment was 12.0 months (4.0-19.1) months and mean (SD) % change in LDL-C after PCSK9i treatment was - 8.6% (12.1). LDL-C reduction from baseline was below 15% in 17/24 patients (70.8%). In the full cohort, mean (SD) minimum LDL-C during PCSK9i treatment was 11.9 (2.8; n = 28) mmol/L. No patient achieved EAS target LDL-C while receiving PCSK9i; genotype analysis suggested LDLR-null/null patients were most refractory to PCSK9i.

CONCLUSION

Response to PCSK9i was minimal in this cohort of patients with HoFH. No patients achieved EAS LDL-C targets, and most failed to reach the EAS-recommended 15% LDL-C reduction for PCSK9i therapy continuation. These results suggest additional LLTs are necessary to achieve LDL-C targets in HoFH.

Homozygous Familial Hypercholesterolemia (HoFH) in Saudi Arabia and Two Cases of Lomitapide Use in a Real-World Setting

Introduction

Homozygous familial hypercholesterolemia (HoFH) is a rare, genetic condition in which mutations in key peptides involved in the low-density lipoprotein receptor (LDL-R) pathway result in markedly elevated levels of circulating LDL-cholesterol (LDL-C). Patients are at high risk of developing early-onset atherosclerotic cardiovascular disease with associated mortality risks. Treatment options are extremely limited, and aspects of society and medical care in Saudi Arabia have the potential to increase incidence and limit treatment pathways in HoFH.

Methods

Along with a brief review of the evidence available on HoFH we describe the treatment of two Saudi Arabian patients with HoFH diagnosed and treated in accordance with local clinical practices and with the microsomal triglyceride transferase protein inhibitor lomitapide.

Results

HoFH in Saudi Arabia is characterized by problems associated with consanguinity, a lack of access to lipoprotein apheresis, and pressures to proceed to liver transplant. Among the case histories, the first patient was commenced on lomitapide therapy, and underwent a dramatic decrease in LDL-C levels from 16.5 to 2.2 mmol/L (87% decrease). This patient had problems with access to lomitapide and cessation of the drug resulted in rebound in LDL-C to 22 mmol/L. The second patient experienced delayed commencement of lomitapide therapy. Despite a 45% decrease in LDL-C levels from 15.3 to 6.9 mmol/L, the patient died the following year at age 26 years from complications subsequent to cardiovascular surgery. Lomitapide was well tolerated in both patients

Discussion

The experience of these two cases highlights the need for prompt, effective, and sustained intervention in HoFH to prevent cardiovascular morbidity and mortality. Lomitapide is an effective therapy for HoFH, and we look forward to improved access to this drug in Saudi Arabia, where there is a chronic unmet medical need in HoFH.

Serum insulin-like growth factor binding protein-1: an improvement over other simple indices of insulin sensitivity in the assessment of subjects with normal glucose tolerance

Background

Insulin resistance is associated with an increased risk of cardiovascular disease and diabetes. It can be assessed using complex reference techniques, such as clamp or frequently sampled intravenous glucose tolerance test (FSIVGTT). Therefore, simple indices derived from fasting insulin and glucose concentrations have been proposed. The aim of this study is to assess fasting serum insulin-like growth factor binding protein-1 (IGFBP-1) as a simple index of insulin sensitivity compared with other simple indices and FSIVGTT.

Methods

Fasting serum IGFBP-1, fasting plasma insulin (FPI), homeostasis model assessment (HOMA-IR), quantitative insulin check index (QUICKI), fasting glucose to insulin ratio (FGIR), Raynaud and insulin glycaemic index (ISI-gly) were correlated with FSIVGTT (Si) in 22 subjects with normal glucose tolerance (NGT) and nine with impaired fasting glucose (IFG).

Results

In NGT individuals, IGFBP-1 correlated more strongly with Si than did any other index both before ( r = 0.76) and after ( r = 0.79) natural logarithm (ln) transformation. In subjects with IFG, IGFBP-1 was weakly correlated with Si before and after ln-transformation ( r = 0.55, r = 0.56, respectively), but ISI-gly was the index most strongly correlated with Si ( r = 0.77, r = 0.85, respectively).

Conclusions

In subjects with NGT, fasting serum IGFBP-1 could be used as a simple reliable marker of insulin sensitivity. For more accurate estimation of insulin sensitivity in normal subjects and those with IFG, ln-transformation is preferred over raw data.