Statistical analysis of serum protein electrophoresis results in External Quality Assessment schemes

in Accreditation and Quality Assurance (2008), 13(3), 149-155

The goal of External Quality Assessment (EQA) schemes is to ensure that results obtained on a particular specimen in a given clinical laboratory are compatible with those obtained by other laboratories on ... [more ▼]

The goal of External Quality Assessment (EQA) schemes is to ensure that results obtained on a particular specimen in a given clinical laboratory are compatible with those obtained by other laboratories on the same specimen. Serum protein electrophoresis is a laboratory test consisting of five fractions (albumin, a1, a2, b and c globulins), which sum up to 100% of total proteins. So far, in EQA schemes the five fractions have been analyzed separately as for ordinary tests like glucose or cholesterol. This approach does not consider the fractions as a whole and the linear relationship between them. A statistical approach has been developed to analyze EQA electrophoresis results from a global standpoint by using robust multivariate method to eliminate the effect of outlying profiles. As illustrated on electrophoretic data from the Belgian EQA scheme, the novel approach improves the detection of poor performing laboratories. The method will be implemented in the Belgian EQA scheme on a routine basis. [less ▲]

Brief introduction to the use of the STATISTICA software

Learning material (2008)

Comparison between player specialization, anthropometric characteristics and jumping ability in top-level volleybal players

in Medicina dello Sport : Rivista di Fisiopatologia dello Sport (2008), 61

Aim. Volleyball is an open skill sport with predominant anaerobic alactic acid power. At higher skill levels, performance characteristics are mainly determined by speed and vertical jumping ability. The ... [more ▼]

Aim. Volleyball is an open skill sport with predominant anaerobic alactic acid power. At higher skill levels, performance characteristics are mainly determined by speed and vertical jumping ability. The aim of this study was to compare anthropometric parameters and jumping ability in a group of elite male volleyball players in relation to technical skills required by player position. Methods. The study population included 36 elite male volleyball players (coming from the Italian First and Second Division Championships). Subjects were grouped by playing position on the court: setters (7); blockers (10); hitters (16); liberos (3). Assessment included anthropometric parameters such as height, weight, body mass index (weight in kg/height in m2), indirect calculation of body fat mass by means of the Katch method (%BFM), measurement of reach with one hand (R1) and two hands (R2); and indirect measurement of explosive strength by means of the Bosco method: squat jump, countermovement jump (CMJ), CMJ with arm swing (CMJas), and repeated jumps for 15 s (R15”); measurement of motor coordination and jumping ability by means of the Vertec test combined with specific offense (Vertec attack [VA]) and defense (Vertec block [VB]) skills. Results. Significant differences were observed between player specialization and anthropometric parameters (height, weight, BMI, R1 and R2). Results of the Bosco (SJ, CMJ, CMJas) and Vertec tests (VA and VB) also differed significantly among the player groups. Conclusion. Functional assessment protocols that evaluate anthropometric characteristics and jumping ability by means of two different unrelated methods, confirming that the two measure different aspects of the same performance, provide more complete indications for selecting players, workload planning and monitoring of player development during training. [less ▲]

Etude exploratoire en vue de la création d’un Observatoire de la santé et du social en Région wallonne

Report (2008)

Characteristics and expectations of patients with erectile dysfunction: results of the SCORED study.

in International Journal of Impotence Research : Official Journal of the International Society for Impotence Research (2008), 20(4), 418-24

In an observational study in men with erectile dysfunction (ED) consulting a general practitioner (GP) or urologist in Belgium, demographics, ED characteristics (including erection hardness score), co ... [more ▼]

In an observational study in men with erectile dysfunction (ED) consulting a general practitioner (GP) or urologist in Belgium, demographics, ED characteristics (including erection hardness score), co-morbidities and treatment expectations were evaluated using a structured questionnaire. In total, 341 GPs and 41 urologists recruited 1492 patients. Most (74%) were untreated and 25% had ED for >3 years. Considering PDE5 inhibitors, erection hardness (89%) and maintenance (92%) were considered 'very important' by most patients. Only 18% of physicians initiated discussion about ED, despite 41% of patients having >or=3 known risk factors. The questionnaire was considered helpful by 81% of GPs and 83% of their patients. Overall, patients are under-diagnosed, and physicians are reluctant to ask about ED. A questionnaire including erection hardness score is useful to facilitate discussion about ED in general practice. Erection hardness and maintenance are more important to patients as compared to fast onset or long duration of action. [less ▲]

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: Frequency, time course and risk factors

in Shock (Augusta, Ga.) (2007), 27(5), 474-481

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We ... [more ▼]

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively. [less ▲]

Evaluation du programme organisé de dépistage du cancer du sein chez les femmes âgées de 50 à 69 ans de la province de Luxembourg. Données 2002 à 2006

Report (2007)

Long-term follow-up reveals low toxicity of radiosurgery for vestibular schwannoma

in Radiotherapy & Oncology (2007), 82(1), 83-89

AIM: The long-term effects of radiosurgery of vestibular schwannomas were investigated in a group of consecutively treated patients. METHODS AND MATERIALS: Between 1995 and 2001, 26 patients (median age ... [more ▼]

AIM: The long-term effects of radiosurgery of vestibular schwannomas were investigated in a group of consecutively treated patients. METHODS AND MATERIALS: Between 1995 and 2001, 26 patients (median age: 67, range: 30-82) with a vestibular schwannoma were treated by Linac-based stereotactic radiosurgery (SRS). The median follow-up was 49 months (16-85 months). Only progressive tumours were treated. The median size of tumours was 18 mm (range 9-30 mm). Before SRS, 11 patients had a useful hearing (Gardner-Robertson classes 1 and 2). Single doses of 10-14 Gy were prescribed at the 80% isodose at the tumour margin. The follow-up consisted of regular imaging with MRI the first 3-6 months after the intervention, followed by additional yearly MRIs, a hearing test and a neurological examination. RESULT: The 5-year-probability of tumour control (defined as stabilization or decrease in size) was 95%. Five-year-probability of preservation of hearing and facial nerve function was 96% and 100%, respectively. Hearing was preserved in 10 out of 11 patients who had a normal or useful hearing at the time of treatment. Mild and transient trigeminal toxicity occurred in 2 (8%) patients. It appeared to be significantly correlated to the dose used (p=0.044). However, only a tendency to significance could be demonstrated in the relationship between the two factors when using the Cox analysis (hazard ratio=1.7; 95% CI: 0.7-3.9; p=0.23). CONCLUSIONS: With the doses used, our study demonstrates that SRS provides an equivalent tumour control rate when compared to surgery, as well as on a long-term basis, an excellent preservation of the facial and the acoustic nerves. Although no permanent trigeminal toxicity was observed, our data confirm that doses below 14 Gy can avoid transient dysesthesias. [less ▲]

Evaluation d'un an de parcours de patients schizophrenes en service psychiatrique liegeois

in Encéphale (L') (2006), 32(5, Pt 1), 722-8

OBJECTIVE: The study was aimed at assessing the clinical evolution and mobility of schizophrenic patients within the healthcare network of the Psychiatric Platform of Liege (Belgium) after a one-year ... [more ▼]

OBJECTIVE: The study was aimed at assessing the clinical evolution and mobility of schizophrenic patients within the healthcare network of the Psychiatric Platform of Liege (Belgium) after a one-year follow-up period. MATERIAL: and methods. The study material consisted of a random sample of 184 patients with schizophrenia drawn from the population of schizophrenic patients treated in the Liege psychiatric care network. The characteristics of these patients have been described previously (18). The 184 patients were followed-up for one-year and reassessed at the end of this period. Mobility (ie, changes between psychiatric care institutions, including home) was recorded for each patient within the institutional network. The diagnosis of schizophrenia was based on the DSM IV. Demographic, social and global functioning (GAF scale) data were collected from the "Resume psychiatrique Minimum (RPM)", a clinical summary which has been imposed by the Belgian Ministry of Public Health for each psychiatric hospital stay. Symptom components were derived from the Psychosis Evaluation tool for Common Use by Caregivers (PECC). RESULTS: Among the 184 patients enrolled in the initial analysis, 6 refused to participate in the follow-up study. The 178 remaining schizophrenic patients included 131 men (74%) and 47 women (26%) with a mean age of 43.1 +/- 13.6 and 48.8 +/- 14.9 years, respectively (p<0.05). The majority of patients (53%) suffered from paranoid schizophrenia. At baseline, 63% of the patients were hospitalised full-time, 6% part-time and 31% received ambulatory care. During the one-year follow-up period, 4 patients died, including one from suicide. When considering mobility, 48% of the patients experienced at least one change of institution, whereas 52% of the patients didn't change at all (see figure 1). The total number of changes over the 1-year period amounted 189, yielding a mean value of 1.1 changes per patient per year. Changes mostly occurred between institutions of similar care setting (see figure 2). Transfers (30%) were also observed directly between hospital and home. A multivariate Poisson regression analysis showed that the number of changes was unrelated to gender and initial care setting but decreased with age (p<0.0001). It was also higher for patients with schizo-affective disorders (2.5 +/- 1.9, p<0.01) or with residual type (1.2 +/- 1.8; p<0.05) than for patients with other types of schizophrenia (ranging from 0.3 +/- 0.5 to 0.9 +/- 1.4). No association was found with initial GAF or PECC, except for negative symptoms (p<0.05). After one year, despite the high proportion of institutional changes (48% of the patients), the distribution of the patients according to care setting remained the same (p=0.77). However, GAF scores significantly improved from 39.7 +/- 16.1 to 44.4 +/- 16.1 (p<0.0001) and likewise for total PECC scores (70 +/- 19.1 vs 63.2 +/- 19.4, p<0.001). Excitatory and disease perception items of the PECC remained unchanged. CONCLUSION: The present study reveals that mobility within the institutional network did affect about half of the schizophrenic patients. Mobility was related to age, type of schizophrenia and disease evolution. Changes occur mainly between psychiatric structures of similar care setting but also directly from hospital to home without passing through an intermediate care structure. Further efforts should be made to provide schizophrenic patients with a more coordinated care provision throughout the course of their disease. [less ▲]

Statistical analysis of electrophoresis results in External Quality Assessment schemes

Poster (2006, July)

The goal of External Quality Assessment (EQA) schemes is to ensure that results obtained on a particular specimen in a given clinical laboratory do not differ significantly from those obtained by other ... [more ▼]

The goal of External Quality Assessment (EQA) schemes is to ensure that results obtained on a particular specimen in a given clinical laboratory do not differ significantly from those obtained by other laboratories on the same specimen. Hence, EQA aims at improving inter-laboratory agreement. Classically, the same blind control specimen is sent to all laboratories and test results are returned to the EQA organizer and analyzed statistically. Robust methods are used to estimate the mean (target value) and standard deviation (SD, inter-laboratory variability) because of the frequent presence of outliers. Laboratories are considered as “poor performers” if their results depart from the target value by a given threshold (e.g., 3×SD). Serum protein electrophoresis is a laboratory test which yields five fractions (albumin, α1, α2, β and γ) which sum up to 100%. So far, EQA schemes have analyzed the five fractions separately as for ordinary tests. Thus, a laboratory is qualified as a poor performer if at least one fraction is out of range. This approach does not take into account the other fractions and the linear relationship between them. A novel statistical approach has been developed to analyze EQA electrophoresis results from a global standpoint by using multivariate standard and robust methods to eliminate the effect of outlying profiles. When applied to electrophoresis data from the Belgian EQA scheme (n = 189 laboratories), the approach has shown that other laboratories should be considered as poor performers than by the classical univariate method. It has also highlighted the need for taking into account the type of electrophoresis assay in judging the laboratory performance. The method will be implemented routinely in the Belgian EQA scheme. [less ▲]