Familial chylomicronemia syndrome: Bringing to life dietary recommendations throughout the life span

PROMIS® and Neuro-QoLTM measures are valid measures of health-related quality of life among patients with familial chylomicronemia syndrome

Background: FCS significantly affects health-related quality of life (HRQOL). Legacy patient-reported outcome measures are often not sensitive to FCS's impact. NIH PROMIS and Neuro-QoL measures may accurately capture HRQOL in FCS patients. This study assessed a broad range of PROMIS and Neuro-QoL measures covering physical, mental, and social HRQOL to determine their suitability for the FCS population.Methods: Adult FCS patients in the United States (N = 25) were recruited to an online survey study and completed several PROMIS short forms and Neuro-QoL computer adaptive tests.Results: Scores were more than 0.5 standard deviations (SD) worse than the normative mean on 10 of 16 normed measures, and more than 0.75 SDs worse than the normative mean on two measures. Responses at the floor and ceiling were occasionally observed, marginal reliabilities were strong, and significant differences across performance status (ps < 0.05) provided preliminary support for construct validity. The measures correlated with each other strongly and as expected.Conclusion: Results support the ability of PROMIS and Neuro-QoL measures to detect HRQOL impairment among patients with FCS. PROMIS and Neuro-QoL measures captured the functional impact and symptom burden associated with FCS, and the broad range of symptom severity experienced by patients with FCS.

Significant Quality of Life Improvement Observed in a Patient With FCS Associated With a Marked Reduction in Triglycerides

Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by severely high triglycerides (TGs). It is associated with a marked increase in risk of recurrent, potentially fatal acute pancreatitis (AP), and symptoms including abdominal pain, fatigue, and anxiety that may substantially reduce quality of life (QoL). A 46-year-old woman with FCS and severely high TGs initially presented with necrotizing pancreatitis with pseudocysts, having previously experienced recurrent AP. The patient reported constant abdominal pain and fatigue, which were evident in her demeanor. Initial management included maximum doses of omega-3 fatty acids and fibrates, plus an extremely restricted diet (reduced intake: calories, fats, simple sugars; no alcohol). Despite adherence to all management strategies, TGs remained at approximately 2800 mg/dL (31.6 mmol/L) and symptoms persisted. The patient was enrolled in COMPASS, a phase 3, placebo-controlled trial to evaluate the effect of an investigational drug, volanesorsen, on fasting TGs in patients with hypertriglyceridemia (fasting TGs ≥ 500 mg/dL [≥5.7 mmol/L]). The woman, a confirmed FCS patient, continued into the open-label extension study, during which fasting TGs decreased to 146 mg/dL (1.7 mmol/L) following 4 months of treatment. The restrictive diet was maintained throughout treatment and no serious adverse events were reported. Along with sustained TG reduction, the patient experienced progressive, perceived improvements in observable QoL measures and a marked reduction in symptom severity and frequency. In a patient with FCS, reduction in TGs following volanesorsen therapy appeared to be associated with marked improvement in clinical symptoms and observed QoL.

Practical definitions of severe versus familial hypercholesterolaemia and hypertriglyceridaemia for adult clinical practice

Diagnostic scoring systems for familial hypercholesterolaemia and familial chylomicronaemia syndrome often cannot differentiate between adults who have extreme dyslipidaemia based on a simple monogenic cause versus people with a more complex cause involving polygenic factors and an environmental component. This more complex group of patients carries a substantial risk of atherosclerotic cardiovascular disease in the case of marked hypercholesterolaemia and pancreatitis in the case of marked hypertriglyceridaemia. Complications are mainly a function of the degree of disturbance in lipid metabolism resulting in elevated lipid levels, so the added value of knowing the precise genetic cause in clinical decision making is unclear and does not lead to clinically meaningful benefit. We propose that for severe elevations of plasma low density lipoprotein cholesterol or triglyceride, the primary factor driving intervention should be the biochemical perturbation rather than the clinical risk score. This underscores the importance of expanding the definition of severe dyslipidaemias and to not rely solely on clinical scoring systems to identify individuals who would benefit from appropriate treatment approaches. We advocate for the use of simple, practical, clinical, and largely biochemically based definitions for severe hypercholesterolaemia (eg, LDL cholesterol >5 mmol/L) and severe hypertriglyceridaemia (triglyceride >10 mmol/L), which complement current definitions of familial hypercholesterolaemia and familial chylomicronaemia syndrome. Irrespective of the precise genetic cause, individuals diagnosed with severe hypercholesterolaemia and severe hypertriglyceridaemia require intensive therapy, including special consideration for new effective but more expensive therapies.

Differentiating Familial Chylomicronemia Syndrome From Multifactorial Severe Hypertriglyceridemia by Clinical Profiles

Context

Differentiation between familial chylomicronemia syndrome (FCS, type 1 hyperlipoproteinemia), a rare metabolic disorder, and the more common multifactorial severe hypertriglyceridemia (sHTG, type 5 hyperlipoproteinemia) is challenging because of their overlapping symptoms but important in patient management.

Objective

To assess whether readily obtainable clinical information beyond triglycerides can effectively diagnose and differentiate patients with FCS from those with sHTG, based on well-curated data from two intervention studies of these conditions.

Methods

The analysis included 154 patients from two phase 3 clinical trials of patients with sHTG, one cohort with genetically confirmed FCS (n = 49) and one with multifactorial sHTG (n = 105). Logistic regression analyses were performed to determine the ability of variables (patient demographics, medical history, and baseline lipids, individually or in sets) to differentiate the patient populations. Receiver operating characteristics were used to determine the variable sets with the highest accuracy (percentage of times actual values matched predicted) and optimal sensitivity and specificity.

Results

The primary model diagnosed 45 of 49 patients with FCS and 99 of 105 patients with sHTG correctly. Optimal sensitivity for all available parameters (n = 17) was 91.8%, optimal specificity was 94.3%, and accuracy was 93.5%. Fasting low-density lipoprotein cholesterol (LDL-C) provided the highest individual predictability. However, a three-variable set of ultracentrifugally measured LDL-C, body mass index, and pancreatitis history differentiated the diseases with a near similar accuracy of 91.0%, and adding high-density lipoprotein cholesterol and very low-density lipoprotein cholesterol for a five-variable set provided a small incremental increase in accuracy (92.2%).

Conclusions

In the absence of genetic testing, hypertriglyceridemic patients with FCS and sHTG can be differentiated with a high degree of accuracy by analyzing readily obtainable clinical information.

Review of current evidence and clinical recommendations on the effects of low-carbohydrate and very-low-carbohydrate (including ketogenic) diets for the management of body weight and other cardiometabolic risk factors: A scientific statement from the National Lipid Association Nutrition and Lifestyle Task Force

Historically, low-carbohydrate (CHO) and very-low-CHO diets have been used for weight loss. Recently, these diets have been promoted for type 2 diabetes (T2D) management. This scientific statement provides a comprehensive review of the current evidence base available from recent systematic reviews and meta-analyses on the effects of low-CHO and very-low-CHO diets on body weight, lipoprotein lipids, glycemic control, and other cardiometabolic risk factors. In addition, evidence on emerging risk factors and potential safety concerns of low-CHO and very-low-CHO diets, especially for high-risk individuals, such as those with genetic lipid disorders, was reviewed. Based on the evidence reviewed, low-CHO and very-low-CHO diets are not superior to other dietary approaches for weight loss. These diets may have advantages related to appetite control, triglyceride reduction, and reduction in the use of medication in T2D management. The evidence reviewed showed mixed effects on low-density lipoprotein cholesterol levels with some studies showing an increase. There was no clear evidence for advantages regarding effects on other cardiometabolic risk markers. Minimal data are available regarding long-term (>2 years) efficacy and safety. Clinicians are encouraged to consider the evidence discussed in this scientific statement when counseling patients on the use of low-CHO and very-low-CHO diets.

The biochemical and genetic diagnosis of lipid disorders

PURPOSE OF REVIEW

To examine recent advances in our knowledge on the diagnosis of lipid disorders.

RECENT FINDINGS

Fasting values above the 99th percentile for direct LDL-cholesterol (LDL-C), lipoprotein(a), and triglycerides are greater than 225 mg/dl, greater than 160 mg/dl, and greater than 500 mg/dl (>5.82, >394, and >5.65 mmol/l), respectively, whereas such values for plasma lathosterol, β-sitosterol, and cholestanol are greater than 8.0, 8.0, and 5.0 mg/l (>0.021, 0.019, and 0.013 mmol/l), respectively. Values below the first percentile for LDL-C are less than 40 mg/dl (<1.03 mmol/l) and for HDL-cholesterol (HDL-C) less than 25 mg/dl (<0.65 mmol/l) in men and less than 30 mg/dl (<0.78 mmol/l) in women, respectively. The above values can predispose to premature CVD, pancreatitis, neurologic disease, and kidney failure, and may be associated with monogenic lipid disorders. In the absence of secondary causes including diabetes or kidney, liver, or thyroid disease, consideration should be given to sequencing the following genes: ABCA1, ABCG5, ABCG8, APOA1, APOA5, APOB, APOC2, APOE, CETP, CYP27A1, GPIHBP1, LCAT, LDLR, LDLRAP1, LIPA, LIPC, LMF1, LPL, MTTP, PCSK9, SCARB1, and STAP1.

SUMMARY

Recent data indicate that secondary causes and a wider range of conditions need to be considered in identifying the underlying causes of hypercholesterolemia, hypertriglyceridemia, hyperalphalipoproteinemia, hypobetalipoproteinemia, and HDL deficiency. Identifying such disorders allows for a more precise assessment of prognosis and the formulation of optimal therapy.

Triglycerides: Emerging Targets in Diabetes Care? Review of Moderate Hypertriglyceridemia in Diabetes

PURPOSE OF REVIEW

Moderate hypertriglyceridemia is exceedingly common in diabetes, and there is growing evidence that it contributes to residual cardiovascular risk in statin-optimized patients. Major fibrate trials yielded inconclusive results regarding the cardiovascular benefit of lowering triglycerides, although there was a signal for improvement among patients with high triglycerides and low high-density lipoprotein (HDL)-the "diabetic dyslipidemia" phenotype. Until recently, no trials have examined a priori the impact of triglyceride lowering in patients with diabetic dyslipidemia, who are likely among the highest cardiovascular-risk patients.

RECENT FINDINGS

In the recent REDUCE IT trial, omega-3 fatty acid icosapent ethyl demonstrated efficacy in lowering cardiovascular events in patients with high triglycerides, low HDL, and statin-optimized low-density lipoprotein (LDL). The ongoing PROMINENT trial is examining the impact of pemafibrate in a similar patient population. Emerging evidence suggests that lowering triglycerides may reduce residual cardiovascular risk, especially in high-risk patients with diabetic dyslipidemia.