Cost-of-illness analysis and regression modeling in cystic fibrosis: a retrospective prevalence-based study

BACKGROUND

Economic data pertaining to cystic fibrosis (CF), is limited in Europe generally, and completely lacking in Central and Eastern Europe. We performed an analysis of all direct costs associated with CF relative to key disease features and laboratory examinations.

METHODS

A retrospective prevalence-based cost-of-illness (COI) study was performed in a representative cohort of 242 CF patients in the Czech Republic, which represents about 65 % of all Czech CF patients. Medical records and invoices to health insurance companies for reference year 2010 were analyzed.

RESULTS

The mean total health care costs were €14,486 per patient, with the majority of the costs going towards medicinal products and devices (€10,321). Medical procedures (€2676) and inpatient care (€1829) represented a much smaller percentage of costs. A generalized linear model showed that the strongest cost drivers, for all cost categories, were associated with patient age and lung disease severity (assessed using the FEV1 spirometric parameter), when compounded by chronic Pseudomonas aeruginosa airway infections. Specifically, maximum total costs are around the age 16 years; a FEV1 increase of 1 % point represented a cost decrease of: 0.9 % (medicinal products), 1.7 % (total costs), 2.8 % (procedures) and 7.0 % (inpatient care).

CONCLUSIONS

COI analysis and regression modeling using the most recent data available can provide a better understanding of the overall economic CF burden. A comparison of our results with other methodologically similar studies demonstrates that although overall costs may differ, FEV1 can nonetheless be utilized as a generally transferrable indicator of the relative economic impact of CF.

Quality assessment of expert answers to lay questions about cystic fibrosis from various language zones in Europe: the ECORN-CF project

Background

The European Centres of Reference Network for Cystic Fibrosis (ECORN-CF) established an Internet forum which provides the opportunity for CF patients and other interested people to ask experts questions about CF in their mother language. The objectives of this study were to: 1) develop a detailed quality assessment tool to analyze quality of expert answers, 2) evaluate the intra- and inter-rater agreement of this tool, and 3) explore changes in the quality of expert answers over the time frame of the project.

Methods

The quality assessment tool was developed by an expert panel. Five experts within the ECORN-CF project used the quality assessment tool to analyze the quality of 108 expert answers published on ECORN-CF from six language zones. 25 expert answers were scored at two time points, one year apart. Quality of answers was also assessed at an early and later period of the project. Individual rater scores and group mean scores were analyzed for each expert answer.

Results

A scoring system and training manual were developed analyzing two quality categories of answers: content and formal quality. For content quality, the grades based on group mean scores for all raters showed substantial agreement between two time points, however this was not the case for the grades based on individual rater scores. For formal quality the grades based on group mean scores showed only slight agreement between two time points and there was also poor agreement between time points for the individual grades. The inter-rater agreement for content quality was fair (mean kappa value 0.232 ± 0.036, p < 0.001) while only slight agreement was observed for the grades of the formal quality (mean kappa value 0.105 ± 0.024, p < 0.001). The quality of expert answers was rated high (four language zones) or satisfactory (two language zones) and did not change over time.

Conclusions

The quality assessment tool described in this study was feasible and reliable when content quality was assessed by a group of raters. Within ECORN-CF, the tool will help ensure that CF patients all over Europe have equal possibility of access to high quality expert advice on their illness.

Genetic variants of transferrin in cystic fibrosis

BACKGROUND

Genetic polymorphism of serum transferrin (Tf) was studied in order to differentiate between protein genetic variants and congenital disorders of glycosylation (CDG), further focusing on unusual findings.

METHODS

Screening of Tf hypoglycosylation was carried out by isoelectric focusing with direct immunofixation and Coomassie blue staining in 100 healthy controls and a group of 1247 patients with various symptoms and diagnoses.

RESULTS

Of the seven different genotypes detected, a significantly higher (p = 0.004) frequency of Tf C1C2 was found among 92 patients with cystic fibrosis; only the most severe DF508 mutation (in either homozygous or heterozygous form) was regularly present in the carriers of this Tf genotype, in contrast to those with the Tf C1C1 variant.

CONCLUSIONS

Association of Tf C2 allele with various malfunctions has been noticed before, but is so far unresolved. This is the a report on increased frequency of Tf C1C2 genotype found in cystic fibrosis. Analysis of larger samples and independent confirmation of our results are needed.

Serum alpha-glutathione S-transferase as a sensitive marker of hepatocellular damage in patients with cystic fibrosis

The aim of the study was to evaluate serum a-glutathione S-transferase (s-GSTA) levels in patients with cystic fibrosis (CF) and to compare s-GSTA with other liver function tests and with a hepatic ultrasound scan (US). The cytosolic enzyme, alpha-glutathione S-transferase is predominantly found in the liver and is distributed uniformly in the liver tissue. In our study s-GSTA levels were measured in 37 CF patients aged 1 to 28 years (mean age 10.4 years, 24 males). The control group consisted of 27 patients aged 2 to 17 years (mean age 8.5 years, 18 males). The presence of hepatobiliary abnormalities was assessed by clinical examination, ultrasound scan, s-GSTA, and conventional liver enzymes: alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST) and gama-glutamyl transferase (GMT). The calculated 5-95 % range of s-GSTA for the control group was 0.098-2.54 microg/l, for the CF group 0.43-9.76 microg/l. Mean s-GSTA level in the control group was 1.55 microg/l (S.D.=1.57), and 2.05 micro/l (S.D.=2.60) in the CF group. In the group of CF patients, the serum levels were significantly higher than in the control group (P<0.01). No significant correlation existed in the CF group between s-GSTA and conventional liver tests (ALT, AST, ALP and GMT). Four patients in the CF group had hepatobiliary abnormalities detectable by conventional liver tests, s-GSTA and US. Four patients had abnormal s-GSTA, while conventional liver tests and US were normal. One other patient had abnormal hepatic US, but normal standard liver tests and s-GSTA. The study has suggested that a raised s-GSTA level might be a marker of possible pathological changes of the hepatobiliar system in CF patients. Serum GSTA seems to be a more sensitive marker than transaminases for the monitoring of hepatocellular integrity and as an early predictor of hepatic damage.

[Evaluation of three dosage regimens of amikacin using pharmacokinetic models in patients with cystic fibrosis]

BACKGROUND

Once-daily administration of aminoglykosides is routinely used, but comparative efficacy data for patients with cystic fibrosis are not available.

METHODS AND RESULTS

The aim of the this study was to compare the predicted pharmacodynamic (PD) activity of amikacin at 28 mg/kg/den administered every 24 hod.(q24h), q12h, and q8h. Pharmacokinetic (PK) data were derived from analysis of the amikacin serum concentration from 42 CF children patients. Individual pharmacokinetics values were used to construct serum concentration--versus time curves and to determine various indices (c peak/MIC ratio and time during the concentration was less than the MIC--T < MIC) for all three dose regimens described above. MIC (minimal inhibitory concentration) for Pseudomonas aeruginosa was 4 mg/l. Significantly lower c peak/MIC but shorter T < MIC were noted when regimens of q8h versus q12h (p < 0.001), q8h vs. q24h (p < 0.001) and q12h vs. q24h (p < 0.001) were compared. This analysis suggests that the potential advantage of achieving a greater c peak/MIC with once-daily aminoglycoside administration may be neutralized by the significantly greater T < MIC in CF patients compared with that achieved with multiple-daily-dosing regimens.

CONCLUSIONS

Routine use of once daily amikacin administration could not be recommended until the clinical data confirming efficiency of this dose modality are available.

Lung transplantation for cystic fibrosis: immune system and autoimmunity

BACKGROUND

In the current study we focused on changes in the immune parameters of patients with CF after lung transplantation (Tx), with particular emphasis on the interaction of the immune system, infection, the autoimmune phenomenon observed in some CF patients, and immunosuppression.

MATERIAL AND METHODS

Seven transplant patients with CF were investigated, 3 men and 4 women; the average age at Tx was 24.2 years (20.2-32.3). The parameters of both humoral immunity (immunoglobulins, complement, CRP, antinuclear and antineutrophil cytoplasmic antibodies) and cellular immunity (T and B lymphocytes, NK cells) were traced.

RESULTS

We observed marked initial hyperimmunoglobulinemia, with a sharp drop in immunoglobulin levels within 1 month after Tx. Positivity for antineutrophil cytoplasmic antibodies (ANCA) was found in 3 patients before Tx. A strong ANCA positivity persisted 2 months after Tx despite deep introductory immunosuppression. In one patient ANCA positivity, after a transient negative result at months 2 and 12 after Tx, reappeared one year after Tx. The Burkholderia cepacia infections found in 2 patients proved to be lethal.

CONCLUSIONS

In our series of CF lung transplant recipients, we found Burkholderia cepacia infection to be a risk factor. The robust appearance of autoantibodies and their persistent positivity for many months despite deep immunosuppression is a remarkable feature observed in some CF patients.

Insulin-like growth factor-I and insulin-like growth factor-binding protein-3 in cystic fibrosis: a positive effect of antibiotic therapy and hyperalimentation

Patients with cystic fibrosis (CF) are underweight and growth retarded. This study tested the link between serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-3 (IGFBP-3) levels and body height, nutritional status, pulmonary function tests and activity of inflammation in 92 subjects with CF (age 2.1-18.8 y). It also analysed the effect of short-term antibiotic treatment and hyperalimentation on IGF-I and IGFBP-3 levels in 33 subjects (age 3.6-33.7y) on 41 occasions. Both IGF-I (-1.19 +/- 0.17 SD) and IGFBP-3 levels (-0.66 +/- 0.12 SD; both p < 0.0001 vs 0) were decreased in cross-sectional measurements. Their standardized values were inversely proportional to age (IGF-I: r = -0.23, p = 0.03; IGFBP-3: r = -0.29, p = 0.005) and positively correlated with SDS of height (IGF-I: r = 0.40, p < 0.0001; IGFBP-3: r = 0.36, p = 0.0005) and of mid-arm circumference (IGF-I: r = 0.39, p = 0.0001; IGFBP-3: r = 0.38, p = 0.0002), and with pulmonary function tests. After a short-term course of intensive antibiotic therapy and hyperalimentation, IGF-I normalized (from -0.66 +/- 0.20 to 0.00 +/- 0.25 SD; p < 0.0001) and IGFBP-3 increased (from -0.78 +/- 0.15 to -0.53 +/- 0.16 SD; p = 0.002). IGFBP-3 correlated inversely with erythrocyte sedimentation rate (r = -0.40, p = 0.01).

CONCLUSION

The levels of IGF-I and IGFBP-3 are markedly decreased in patients with CF and tend to normalise after a short course of antibiotic treatment and hyperalimentation.

Characterization of a novel 21-kb deletion, CFTRdele2,3(21 kb), in the CFTR gene: a cystic fibrosis mutation of Slavic origin common in Central and East Europe

We report a large genomic deletion of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, viz., a deletion that is frequently observed in Central and Eastern Europe. The mutation, termed CFTRdele2,3(21 kb), deletes 21,080 bp spanning introns 1-3 of the CFTR gene. Transcript analyses have revealed that this deletion results in the loss of exons 2 and 3 in epithelial CFTR mRNA, thereby producing a premature termination signal within exon 4. In order to develop a simple polymerase chain reaction assay for this allele, we defined the end-points of the deletion at the DNA sequence level. We next screened for this mutation in a representative set of European and European-derived populations. Some 197 CF patients, including seven homozygotes, bearing this mutation have been identified during the course of our study. Clinical evaluation of CFTRdele2,3(21 kb) homozygotes and a comparison of compound heterozygotes for deltaF508/CFTRdele2,3(21 kb) with pairwise-matched deltaF508 homozygotes indicate that this deletion represents a severe mutation associated with pancreatic insufficiency and early age at diagnosis. Current data show that the mutation is particularly common in Czech (6.4% of all CF chromosomes), Russian (5.2%), Belorussian (3.3%), Austrian (2.6%), German (1.5%), Polish (1.5%), Slovenian (1.5%), Ukrainian (1.2%), and Slovak patients (1.1%). It has also been found in Lithuania, Latvia, Macedonia and Greece and has sporadically been observed in Canada, USA, France, Spain, Turkey, and UK, but not in CF patients from Bulgaria, Croatia, Romania or Serbia. Haplotype analysis has identified the same extragenic CF-haplotype XV-2c/KM. 19 "A" and the same infrequent intragenic microsatellite haplotype 16-33-13 (IVS8CA-IVS 17bTA-IVS 17bCA) in all examined CFTRdele2,3(21 kb) chromosomes, suggesting a common origin for this deletion. We conclude that the 21-kb deletion is a frequent and severe CF mutation in populations of Eastern- and Western-Slavic descent.

[Cystic fibrosis--a disease of adolescents and adults?]

BACKGROUND

Cystic fibrosis (CF) is no longer a childhood disease. Since the identification of the gene in 1989 research has made advances and changed views on the pathogenesis, diagnosis and treatment. The objective of the present work is to make doctors treating adult patients familiar with modern therapeutic methods and their value.

METHODS AND RESULTS

In the CF Centre of the Faculty Hospital in Prague Motol 349 patients are followed up on a long-term basis, incl. 95 who died since 1985. Hundred and twenty six (36.1%) patients survived to the age of 18 years, of those 41 died and 85 patients live. Comparison of semilongitudinal data of a group of 83 patients born before 1975 whose treatment during childhood and puberty was inadequate and 196 patients born in 1976-90 treated by modern methods proved the great effect of treatment on the course and prognosis of the disease. The median age at death increased during from 12.2 years in 1985-90 to 18.8 years in 1991-1998 (p = 0.004). The nutritional status of adult patients is satisfactory in 40.4%, poor in 33.3% and marginal in 26.3%. A normal pulmonary function was recorded in 17.5%, 22.8% are severely affected, the majority of patients (59.7%) has values within 40 to 80% of normal levels.

CONCLUSIONS

Modern intensive treatment improved the prognosis and quality of live in patients with CF. Critical deterioration of the clinical condition shifted to the threshold of adult age. It is therefore essential that doctors treating such patients should be familiar with this issue.

Antineutrophil cytoplasmic autoantibodies (ANCA) in children with cystic fibrosis

Anti-neutrophil cytoplasmic antibodies (ANCA) represent a useful diagnostic tool in patients with small vessel vasculitis. Circulating ANCA specific for bactericidal/permeability increasing protein (BPI) have been recently reported in adult patients with cystic fibrosis (CF), an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene with consequent impaired function of a transmembrane chloride channel. To contribute to the better understanding of the significance of ANCA in this disease, we investigated ANCA presence and antigenic specificity in children with CF. Results were correlated with clinical status, immunological data, age and genotype. The indirect immunofluorescence pattern of a total of 71 children with CF indicated that 31 were c-ANCA positive, while seven were p-ANCA positive. In further ELISA studies of ANCA antigenic specificity, 51 out of 66 investigated samples were positive for BPI, and 14 out of 28 were positive for proteinase 3 (PR3). We found an association between levels of antibodies against PR3 with age and Pseudomonas infection. We did not, however, find any correlation between CFTR genotypes, Pseudomonas infection or paediatric parameters and the level of anti-BPI antibodies. High positivity of anti-BPI antibodies were seen even among the youngest CF patients, before the development of clinical signs of CF, indicating that formation of ANCA might be a very early event in the disease. Both anti-BPI and anti-PR3 antibodies may play a significant, although variable role, in the pathogenesis of CF.

[Strategies in prenatal diagnosis of cystic fibrosis after the introduction of DNA analysis. Initial experience]

The authors describe their experience with the prenatal genetic diagnosis of cystic fibrosis (CF), using DNA analysis in the first trimester of pregnancy in three families with a 25% risk of CF. The authors examined polymorphisms of probes J3.11, met D, met H, KM-19 and XV-2c. All families were fully informative when one or two probes were used. In two families the development of unaffected children--carriers of the gene for CF was proved. In one of these foetuses in the 17th and 21st week false pathological values of microvilillous enzymes were assessed. With regard to this possibility the authors do not recommend to supplement the DNA analysis in the first trimester by biochemical examination of amniotic fluid. The results were confirmed by delivery of unaffected children. In one family DNA analysis revealed the development of an unaffected homozygote, the pregnancy was, however, terminated by a miscarriage. In women with an increased risk of abortion the authors recommend therefore to make the molecular genetic examination during the second trimester from amniotic fluid cells.

[Experience with rapid molecular genetic diagnosis using the polymerase chain reaction]

The authors give an account of their experience with 1000 amplifications of DNA by the polymerase chain reaction for the prenatal diagnosis of cystic fibrosis. The method is demonstrated on examples of examinations of the informativity value and prenatal diagnosis in the first trimester of pregnancy in families with a 25% risk of cystic fibrosis, using J 3.11 (Msp I), met H (Msp I), KM 19 (Pst I), CS 7 (Hha I), Mp6d9 (Msp I), XV 2c (Taq I) probes. The authors summarize methodical check-up and safety measures to ensure the reliability of diagnoses made by the PCR method.

Comparison of the effect of three oral mucolytics on the ultrastructure of the tracheal epithelium in rabbits

The effect of the application of a single oral dose of 100 mg of three mucolytic agents (N-acetylcysteine, carbocysteine and Na-2-mercaptoethane sulphonate) on the ultrastructure of the tracheal epithelium of healthy rabbits was studied. Due to the function of oral mucolytics the goblet cells were overstimulated and injured. Na-2-mercaptoethane sulphonate was the least irritating substance. Acetylcysteine produced the most pronounced injury of the goblet cells, followed by rapid differentiation of these cells. Oral administration of all mucolytics studied caused local impairment of mucus flow in the airways.

Chest physiotherapy and airway obstruction in patients with cystic fibrosis - a negative report

In 24 patients with cystic fibrosis (6-20 years old), divided into two groups, we studied indices of airways obstruction before, 20-30 min and 2 h after chest physiotherapy. The physiotherapy lasted for 30 min and included expectoration of 2-10 ml of sputum. In one group of 14 patients, studies were made only 30 min after chest physiotherapy. No significant improvements of the ventilatory tests occurred. In fact, Vmax at 25% of VC deteriorated (P less than 0.05) in this group as a whole. In some patients also CV/VC increased, and N2 and CO2 alveolar slopes became steeper. Only Gaw/TGV improved in 20% of the patients by more than 10% of the control value. In the second group of 10 patients, ventilatory studies were repeated 3 times at one month intervals. They did not change significantly at 20 min and 2 h after chest physiotherapy. Gaw/TGV value improved by more than 10% in 20% of the patients. During chest physiotherapy, the patients were stimulated to cough. This might contribute to the immediate negative effects on ventilatory function by causing collapse of the central airways, as documented by cinebronchographic studies in 8 patients.