The correlation of the serum level of L-carnitine with disease severity in patients with Amyotrophic lateral sclerosis

BACKGROUND

The relationship between reserve of L-carnitine and severity in patients with Amyotrophic lateral sclerosis (ALS) is not studied sufficiently. We decided to measure the serum levels of L-carnitine in patients and the relationship with ALS severity.

METHOD

This cross-sectional study evaluated the serum levels of L-carnitine in 30 patients with ALS (total-case) divided into two groups included 15 patients in the Oral-Fed (OF) group and 15 patients in the Enteral-Fed (EF) group, compared with 15 healthy people matched in age and sex in the control group. We measured the body mass index (BMI), daily intake of L-carnitine, amyotrophic lateral sclerosis functional rating scale (ALSFRS), and serum L-carnitine level in all participants and compared among groups.

RESULTS

Serum L-carnitine (p < 0.001) and BMI (p = 0.03) were significantly lower in the total-case group compared to the control group. Alternatively, the serum level of L-carnitine (p = 0.001), ALSFRS (p < 0.001), BMI (p = 0.007), and dietary L-carnitine intake (p = 0.002) were significantly higher in OF group compared with EF. Higher serum L-carnitine levels were associated with a higher score of ALSFRS (β = 0.46, P = 0.01) in the total-case group.

CONCLUSION

Our study's results showed that serum levels of L-carnitine were lower in patients with ALS in comparison to healthy people. Also, the lower serum level of L-carnitine was associated with the higher severity of the disease.

Kennedy's disease 1234 scale: Preliminary design and test

Kennedy's disease (KD), also known as spinal and bulbar muscular atrophy (SBMA), is a rare x-linked genetic disorder which is characterized by muscle weakness and atrophy. In previous clinical trials, KD patients had been assessed using the ALSFRS scale, which was specifically designed for ALS patients. However, the progression of KD is very slow, and thus, the ALSFRS does not accurately reflect changes in the clinical condition of KD patient. Here, we developed the KD 1234 scale which designed specially for KD. We evaluated KD 1234 and ALSFRS in 81 KD patients and 100 healthy age-matched male participants. Of 81 cases, 52 were followed up after 32months. Scale reliability was assessed using inter-rater reliability, split-half reliability and internal consistency reliability (Cronbach's α coefficient). Scale validity was evaluated using content and structure validity. Longitudinal analysis was performed. The results showed the KD 1234 scale was simple and easy to operate, with good reliability, validity and reactivity. We think this new scale can quantitatively evaluate the clinical condition of KD patients and any changes in this condition, and is thus suitable for clinical studies.

Item response theory analysis of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised in the Pooled Resource Open-Access ALS Clinical Trials Database

Our objective was to examine dimensionality and item-level performance of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) across time using classical and modern test theory approaches. Confirmatory factor analysis (CFA) and Item Response Theory (IRT) analyses were conducted using data from patients with amyotrophic lateral sclerosis (ALS) Pooled Resources Open-Access ALS Clinical Trials (PRO-ACT) database with complete ALSFRS-R data (n = 888) at three time-points (Time 0, Time 1 (6-months), Time 2 (1-year)). Results demonstrated that in this population of 888 patients, mean age was 54.6 years, 64.4% were male, and 93.7% were Caucasian. The CFA supported a 4* individual-domain structure (bulbar, gross motor, fine motor, and respiratory domains). IRT analysis within each domain revealed misfitting items and overlapping item response category thresholds at all time-points, particularly in the gross motor and respiratory domain items. Results indicate that many of the items of the ALSFRS-R may sub-optimally distinguish among varying levels of disability assessed by each domain, particularly in patients with less severe disability. Measure performance improved across time as patient disability severity increased. In conclusion, modifications to select ALSFRS-R items may improve the instrument's specificity to disability level and sensitivity to treatment effects.