4-Pyridoxic Acid/Pyridoxine Ratio in Patients with Type 2 Diabetes is Related to Global Cardiovascular Risk Scores.

BACKGROUND: Vascular diseases are multifactorial and several risk factors may have synergetic effect on the global vascular risk. Among patients with diabetes, we investigated whether vitamin B6 species differ according to global cardiovascular risk. METHODS: The present observational study included 122 patients with type 2 diabetes (mean (SD) age = 69.9 (9.1) years; 50% men). Concentrations of vitamin B6 vitamers were measured. Classical blood biomarkers and risk factors were used to compute a multivariate risk score. RESULTS: Plasma concentrations of 4-pyridoxic acid were higher in patients with high risk versus those with low risk scores (48.2 (63.7) vs. 31.9 (15.0) nmol/L; p = 0.031). Plasma pyridoxine was significantly lowered in patients at high risk (2.8 (28.4) vs. 38.1 (127.8) nmol/L; p = 0.003). PAr index (4-pyridoxic acid/pyridoxal + pyridoxal 5'-phosphate) (1.05 (0.07) vs. 0.84 (0.06); p = 0.017) and the ratio of 4-pyridoxic acid/pyridoxine (7.0 (4.8) vs. 3.9 (3.2); p < 0.001) were higher in patients at high risk. After adjustment for cystatin C and C-reactive protein, only pyridoxine and 4-pyridoxic acid/pyridoxine ratio remained significantly different according to vascular risk scores. 4-Pyridoxic acid/pyridoxine ratio was the best marker to discriminate between patients according to their risk scores-area under the curve (AUC) (95% confidence intervals (CI)) = 0.72 (0.62⁻0.81). 4-Pyridoxic acid/pyridoxine ratio was directly related to plasma levels of soluble vascular cell adhesion molecule 1. CONCLUSION: Vitamin B6 metabolism was shifted in patients with multiple vascular risk factors. The catabolism to 4-pyridoxic acid was enhanced, whereas the catabolism to pyridoxine was lowered. High 4-Pyridoxic acid/pyridoxine ratio is independently associated with global cardiovascular risk.

Factors Predicting Survival in ALS Patients--Data from a Population-Based Registry in Rhineland-Palatinate, Germany.

BACKGROUND: The possibility to survive with amyotrophic lateral sclerosis (ALS) varies considerably and survival extends from a few months to several years. A number of demographic and clinical factors predicting survival have been described; however, existing data are conflicting. We intended to predict patient survival in a population-based prospective cohort of ALS patients from variables known up to the time of diagnosis. METHODS: Incident ALS patients diagnosed within three consecutive years were enrolled and regularly followed up. Candidate demographic and disease variables were analysed for survival probability using the Kaplan-Meier method. The Cox proportional hazard regression model was used to assess the influence of selected predictor variables on survival prognosis. RESULTS: In the cohort of 193 patients (mean age 65.8, standard deviation 10.2 years), worse prognosis was independently predicted by older age, male gender, bulbar onset, probable or definite ALS according to El Escorial criteria, shorter interval between symptom onset and diagnosis, lower Functional Rating Scale, diagnosis of frontotemporal dementia, and living without a partner. CONCLUSIONS: Taking into account these predictor variables, an approximate survival prognosis of individual ALS patients at diagnosis seems feasible.

Vitamin B status in patients with type 2 diabetes mellitus with and without incipient nephropathy.

AIM: To investigate the vitamin B status, with particular focus on vitamin B6, in adults with and without incipient nephropathy secondary to type 2 diabetes mellitus. METHODS: Plasma and/or urine concentrations of vitamins B6, B1, B12, related vitamers and biomarkers (including total homocysteine, methylmalonic acid) were measured in 120 adults with type 2 diabetes (including 46 patients with microalbuminuria) and 52 non-diabetic control subjects. RESULTS: Plasma concentrations of pyridoxal 5'-phosphate (PLP) were significantly lower in patients with type 2 diabetes than in control subjects (median: 22.7 nmol/L, diabetes with microalbuminuria; 26.8 nmol/L, diabetes without microalbuminuria; 39.5 nmol/L, non-diabetic control; p<0.0001). The prevalence of low PLP (<30 nmol/L) was 63%, 58%, and 25% in the diabetes groups with and without microalbuminuria and the control group, respectively. Plasma levels of pyridoxine and pyridoxal were also lower (p<0.0001), but levels of pyridoxamine, pyridoxamine 5'-phosphate, and pyridoxic acid were higher in both groups with diabetes compared to the control group (p<0.001). Thiamine deficiency was highly prevalent in all groups, whereas low vitamin B12 and elevated methylmalonic acid were rare. Increased levels of C-reactive protein and soluble vascular cell adhesion molecule-1 were observed in the groups with diabetes (p<0.05, versus healthy control). CONCLUSIONS: Deficiency of vitamin B6 (PLP, pyridoxine, pyridoxal) and vitamin B1 (thiamine) was prevalent in type 2 diabetes. Incipient nephropathy was associated with more pronounced alterations in vitamin B6 metabolism and stronger indications of endothelial dysfunction and inflammation.

Factors predicting one-year mortality in amyotrophic lateral sclerosis patients--data from a population-based registry.

BACKGROUND: Survival in amyotrophic lateral sclerosis varies considerably. About one third of the patients die within 12 months after first diagnosis. The early recognition of fast progression is essential for patients and neurologists to weigh up invasive therapeutic interventions. In a prospective, population-based cohort of ALS patients in Rhineland-Palatinate, Germany, we identified significant prognostic factors at time of diagnosis that allow prediction of early death within first 12 months. METHODS: Incident cases, diagnosed between October 2009 and September 2012 were enrolled and followed up at regular intervals of 3 to 6 months. Univariate analysis utilized the Log-Rank Test to identify association between candidate demographic and disease variables and one-year mortality. In a second step we investigated a multiple logistic regression model for the optimal prediction of one-year mortality rate. RESULTS: In the cohort of 176 ALS patients (mean age 66.2 years; follow-up 100%) one-year mortality rate from diagnosis was 34.1%. Multivariate analysis revealed that age over 75 years, interval between symptom onset and diagnosis below 7 months, decline of body weight before diagnosis exceeding 2 BMI units and Functional Rating Score below 31 points were independent factors predicting early death. CONCLUSIONS: Probability of early death within 12 months from diagnosis is predicted by advanced age, short interval between symptom onset and first diagnosis, rapid decline of body weight before diagnosis and advanced functional impairment. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01955369, registered September 28, 2013).

Variability and prognostic relevance of different phenotypes in amyotrophic lateral sclerosis - data from a population-based registry.

OBJECTIVES: The clinical spectrum of amyotrophic lateral sclerosis (ALS) is characterized by a considerable variation. Different phenotypes have been described by previous studies. We assessed clinical variability and prognostic relevance of these phenotypes in a prospective, population-based cohort of ALS patients in Rhineland-Palatinate, Germany. METHODS: Incident ALS cases, diagnosed between October 2009 and September 2012, were prospectively enrolled and classified according to established ALS phenotype classification (bulbar, classic, flail arm, flail leg, pyramidal, respiratory). Survival probability was described using Kaplan-Meier method. Moreover, the influence of an additional frontotemporal dementia (FTD) was analysed. RESULTS: Phenotypes of all 200 patients were determined. Bulbar and classic phenotypes accounted for 75% of all cases. Deterioration of functional impairment during disease progression was lowest in flail leg and pyramidal variants, and most pronounced in bulbar and classic phenotypes. A poor survival prognosis was observed for bulbar, classic or respiratory phenotypes. Patients with an additional FTD showed an even worse outcome. CONCLUSIONS: Results suggest that ALS is a heterogeneous disease, as ALS phenotypes differ in disease progression and survival time. Patients classified as suffering from bulbar, classic and respiratory ALS, as well as those with an additional FTD, show a marked reduction of survival time.

Incidence of amyotrophic lateral sclerosis in Rhineland-Palatinate, Germany.

There is a lack of prospective and population based epidemiological data on amyotrophic lateral sclerosis in Germany to date. The ALS registry Rhineland-Palatinate was established to investigate the incidence, course and phenotypic variety of ALS in this south-west German state of about 4 million inhabitants. During the period 2010-2011, consecutive incident patients with amyotrophic lateral sclerosis according to the revised El Escorial criteria were included and followed up using multiple overlapping sources of case ascertainment. One hundred and forty-six patients were enrolled. The annual crude incidence for amyotrophic lateral sclerosis in Rhineland-Palatinate was 1.8/100,000 person-years (95% CI 1.6-2.2). Male to female ratio was 1.1:1. Incidence increased with age reaching a peak in the 70-74 years age group and declined thereafter. Late-onset ALS (≥ 75 years) was found in 14.4% of patients. About 32% of patients presented with bulbar onset. In conclusion, incidence rate of amyotrophic lateral sclerosis in Rhineland-Palatinate is within the range of other prospective population based registers in Europe and North America. Gender ratio is nearly balanced.

A prospective multicentre study on sural nerve action potentials in ALS.

OBJECTIVE: To evaluate sensory nerve conduction studies in ALS in a prospective multicentre study involving 7 neurophysiologists from 6 European countries. METHODS: Bilateral sural potentials were obtained in 35 ALS patients and 35 age-matched controls according to a standardised examination protocol using antidromic surface technique. The recordings from the right sural nerve of the controls were used for reference values. A reduction from the mean of controls greater than 2 SDs was considered abnormal. RESULTS: Reduced sensory nerve action potential (SNAP) amplitude or reduced conduction velocity (CV), or both, was found in 6 ALS patients (17%). Decrease in CV was the most frequent finding, and was observed in 8 nerves from 5 patients. Reduced SNAP amplitude was found in 2 nerves from 2 patients. All changes were minor ranging from -2.1 to -3.2 SDs. CONCLUSIONS: This is the first standardised multicentre study on sensory potentials in ALS. It confirms that although normal sensory findings should be expected in the majority of ALS patients, minor abnormalities are not uncommon. SIGNIFICANCE: Mild sensory abnormalities do not necessarily exclude a diagnosis of ALS.

Influence of peer review medical audit on pathophysiological interpretation of nerve conduction studies in polyneuropathies.

OBJECTIVE: To evaluate the possible influence of peer review medical audit on experienced physicians' pathophysiological interpretation of nerve conduction studies in polyneuropathy patients. METHODS: Since 1992, 7 European neurophysiologists have collected samples of their patient examinations for regular review where the physicians interpret each other's cases electronically and subsequently discuss them at regular workshop meetings (i.e. a form of medical audit). Two sets of 100 polyneuropathy examinations interpreted with an interval of 4-6 years were selected. The sets contained 1456 and 1719 nerve conduction studies, each given a pathophysiological test conclusion by each individual physician. Inter-physician agreement on interpretation of demyelination and axonal loss of the nerve, as well as neuropathic and unspecific findings, was estimated using kappa statistics. RESULTS: Increased agreement from set 1 to set 2 was found on interpretation of demyelination of the nerve (set 1: kappa=0.22; set 2: kappa=0.45), and of neuropathic (set 1: kappa=0.46; set 2: kappa=0.64) and unspecific findings (set 1: kappa=0.35; set 2: kappa=0.54). No changes were found on interpretation of axonal loss (set 1: kappa=0.26; set 2: kappa=0.31) and normal findings (set 1 and set 2: kappa=0.90). CONCLUSIONS: Participation in regular peer review medical audit resulted in increased agreement on interpretation of nerve conduction studies for 6 of the 7 participants. The study further highlights the need for better definition of criteria for identification of demyelinating, and in particular, axonal peripheral neuropathies. SIGNIFICANCE: International collaboration involving peer review medical audit may contribute to development of practice guidelines and, in turn, to increased quality of electrodiagnostic medicine.

Pathophysiology inferred from electrodiagnostic nerve tests and classification of polyneuropathies. Suggested guidelines.

OBJECTIVE: To present criteria for pathophysiological interpretation of motor and sensory nerve conduction studies and for pathophysiological classification of polyneuropathies suggested by a group of European neurophysiologists. METHODS: Since 1992 seven neurophysiologists from six European countries have collected random samples of their electrodiagnostic examinations for peer review medical audit in the ESTEEM (European Standardized Telematic tool to Evaluate Electrodiagnostic Methods) project. Based on existing criteria in the literature, the experience with a patient material of 572 peer reviewed electrodiagnostic examinations, and productive discussions between the physicians at workshops, the collaboration has produced a set of criteria now routinely used at the centres involved in the project. RESULTS: The first part of the paper considers pathophysiology of individual nerve segments. For interpretation of motor and sensory nerve conduction studies, figures showing change in amplitude versus change in conduction velocity/distal latency and change in F-wave frequency versus change in F-wave latency are presented. The suggested boundaries delimit areas corresponding to normal, axonal, demyelinated, or neuropathic nerve segments. Criteria for motor conduction block in upper and lower extremities are schematically depicted using the parameters CMAP amplitude and CMAP duration. The second part of the paper suggests criteria for classification of polyneuropathies into axonal, demyelinating, or mixed using the above-mentioned criteria. CONCLUSIONS: The suggested criteria are developed during many years of collaboration of different centres and may be useful for standardization in clinical neurophysiology. SIGNIFICANCE: Consistent interpretation of nerve conduction studies is an important step in optimising diagnosis and treatment of nerve disorders.