Cost-effectiveness of infliximab in the treatment of rheumatoid arthritis in clinical practice.

OBJECTIVE: We evaluated the cost-effectiveness of infliximab therapy in Finnish RA patients in a real-life clinical setting and identified factors influencing it, using the national register of biological treatment (ROB-FIN). METHODS: A cost-utility analysis was performed, derived from EQ-5D, and related to HAQ score and disease activity using multiple regression. QALYs were calculated based on these utilities, using patient-level data up to the last control registered. Cost-effectiveness analyses included costs per ACR50 responder, and costs per low DAS28 score (<3.2) achieved, in combination with a clinically significant improvement (>1.2). The costs considered were direct medical costs of infliximab and cost of intravenous infusion. Patient-level costs were calculated based on dose and dosage frequency, and were related to the difference in QALYs resulting from infliximab therapy. RESULTS: The 297 patients had been treated with infliximab for an average of 21 months. The HAQ score and patient's global assessment improved significantly on infliximab therapy. More than two-thirds of the patients achieved a clinically important improvement in HAQ. A QALY gain occurred in 76%. 35% of these had an incremental cost-effectiveness ratio of < or =40,000 Euro/QALY gained, the median cost being 51,884 Euro. The cost per QALY gained was significantly lower for patients achieving an ACR50 response at 3, 12 and 24 months. CONCLUSION: Treatment with infliximab and aiming at ACR50 response appears cost-effective, remembering the restrictions of an observational study set up. Current Care guidelines, which require sufficient disease control when deciding on continuing biological therapy, get support from these findings.

The value of the diagnostic criteria in rheumatoid arthritis.

The ARA and the New York diagnostic criteria for rheumatoid arthritis were studied in 411 patients with a recent inflammatory joint disease (100 with RA, 311 with other disease) in order to evaluate their value in distinguishing progressive rheumatoid arthritis from other joint diseases. Rheumatoid factor, symmetrical polyarthritis, morning stiffness, and X-ray changes were of the greatest value in diagnosing RA in the early stage of the disease. Other diagnostic criteria had either a poor specificity or sensitivity, and were thus of less importance as discriminators.

Incidence of inflammatory rheumatic diseases in Finland.

The incidence of inflammatory joint diseases was estimated by using two patient series. Firstly, the total yearly incidence of all such diseases together was estimated in a population of 15 600 persons of 16 years of age or older. Secondly, this overall incidence was divided by the ratio of different diseases obtained from a larger series of patients. The incidence of all inflammatory joint diseases was 218/100 000/year, 182 in males and 250 in females. The incidence was highest in middle age and lowest in old age. The incidence of ill-defined arthritides was five times that of definite rheumatoid arthritis in the youngest age group but in the oldest their frequencies were equal. In the whole population, the proportion of ill-defined arthritides was 2/5, of definite RA 1/5, of HL-A B27 associated diseases 1/5, and of other diseases 1/5 of the total incidence of inflammatory joint diseases. Because the frequency of HL-A B27 in all patients surveyed was about 40%, only half of the patients with this antigen showed a clinical picture of ankylosing spondylitis, Reiter's disease, or reactive arthritis.

Rheumatoid arthritis with pleural effusion includes a subgroup with autoimmune features and HLA-B8, Dw3 association.

Twenty-eight patients with rheumatoid pleural effusion were investigated to examine the frequency of HLA antigens as compared with 56 rheumatoid arthritis (RA) patients without this intrathoracic manifestation of RA and with 283 healthy controls. HLA-B8 was strongly associated with the presence of pleural effusion (PE) in RA patients. A high prevalence (71%) of B8/Dw3 was found among male RA patients of the PE group in whom the joint disease had begun at an age over 50 years and who also had besides pleuritis other intrathoracic manifestations of RA associated with high rheumatoid factor titres and low complement (C4) levels in sera. Actually, the HLA-B8 association was not seen in the rest of the PE group. The finding may be related to the heterogeneity of RA, a male subgroup of the disease being characterized by multiple intrathoracic manifestations and genetically associated with the large group of autoimmune disorders, such as SLE, characterized by high prevalences of HLA-B8 and D(R)3.

Diffuse interstitial lung disease in rheumatoid arthritis. Views on immunological and HLA findings.

Immunological parameters including HLA typing were studied in 32 patients with rheumatoid arthritis (RA) associated diffuse interstitial lung disease (DILD) and in 32 age- and sex-matched RA control patients. The male RA patient group with DILD also included patients with other intrathoracic manifestations and had a higher prevalence of HLA-B8 and Dw3 than did healthy controls, thus agreeing with our earlier results that RA patients with this antigen combination are prone to multiple intrathoracic complications. Patients with DILD had higher titres of rheumatoid factor (RF) and lower complement (C4) levels than matched RA controls. The RF titre was in inverse correlation with C3 and C4 levels, suggesting that RF immune complexes may also promote rheumatoid lung disease via activation of the classical pathway of complement.

Differences in HLA antigens between patients with mixed connective tissue disease and systemic lupus erythematosus.

Patients with mixed connective tissue disease (MCTD, n = 32) or systemic lupus erythematosus (SLE, n = 60) were typed for HLA-A, B, C, Dw, and DR antigens. All patients with SLE fulfilled at least four criteria of SLE and the patients with MCTD met the criteria proposed by Alarcon-Segovia (1989). The presence of antibodies to Sm was not considered as an exclusion for MCTD. In the patients with SLE, Dw3, DR3, and the associated B8 and A1 antigens were increased, whereas in the patients with MCTD an increased frequency of Dw4 was found (45 v 18% in controls v 14% in SLE). Of the subtypes of DR4, Dw4 was present in all but one of the DR4 positive patients. The frequency of DR4 in patients with MCTD (52%) differed significantly from that of controls (28%). The strong association of MCTD to one DR4 subtype was further seen in the significantly increased frequency of the B15, DR4 combination. Thus the genetic background seems to be different in patients with MCTD from that in patients with SLE. This could partly explain the clinical differences between these diseases.

More evidence of distinctive features of mixed connective tissue disease.

A comparison of clinical, immunological and HLA-D region antigen features was made between 22 patients with mixed connective tissue disease (MCTD) and 118 patients with systemic lupus erythematosus (SLE), scleroderma or primary Sjögren's syndrome. The MCTD patients had hypergammaglobulinemia more often than did those with SLE and scleroderma, but had less skin ulceration, serositis, nephritis, central nervous system disease and hypocomplementemia than the SLE patients. The frequencies of HLA-DR4 and its Dw4 subtype were significantly increased in MCTD as compared with both the other patient groups and healthy controls. Anti-RNP antibodies and the clinical characteristics together seem to illustrate a disease syndrome which is clinically and genetically distinct and fits with the prevailing concept of MCTD.

Predictive value of synovial fluid analysis in estimating the efficacy of intra-articular corticosteroid injections in patients with rheumatoid arthritis.

The predictive relevance of synovial fluid analysis and some other variables for the efficacy of intra-articular corticosteroid injections in 30 patients with rheumatoid arthritis and hydropsy in a knee joint was evaluated in a prospective study. At the onset of the study, the knee joints were aspirated and 30 mg triamcinolone hexacetonide injected intra-articularly. The circumferences and the tenderness scores of the knee joints were measured at onset, after two months, and at the end of the six months' follow up. Of the variables studied, synovial fluid C4, percentage of synovial fluid polymorphonuclear leucocytes, blood haemoglobin, and serum C3 correlated significantly with the decrease in knee joint circumference after two months, whereas only the percentage of synovial fluid polymorphonuclear leucocytes correlated significantly after six months. Between the patients with and without improvement in the tenderness scores of the knee joints, only serum IgM differed at the examination after two months; this was higher in patients whose scores showed no improvement.

Different distribution of T cell receptor beta-chain haplotypes in mixed connective tissue disease and systemic lupus erythematosus.

Mixed connective tissue disease (MCTD) and systemic lupus erythematosus (SLE) are autoimmune diseases with a genetic background, and it is reasonable to suggest that aberrations in T cell receptor (TCR) genes could contribute to these diseases, as they play an important role in immune regulation. We studied TCR beta-chain gene segments V beta 8, V beta 11 and C beta with restriction fragment length polymorphism (RFLP) in MCTD and SLE patients and controls. Haplotypes could be assigned in individuals who were homozygous for two or three of these three loci, whereupon the haplotype 2/25/10 (V beta 8/V beta 11/C beta) was found to be under-represented in MCTD (P = 0.029). The frequencies of individual alleles in both groups were similar to those of the controls, whereas the number of homozygotes within V beta 8 gene (23/23 kb and 2/2 kb) was increased in MCTD (P = 0.028). It is concluded that the distribution of TCR beta-chain genes could be aberrant in MCTD and could play a role in susceptibility, whereas the TCR beta-chain gene distribution in the SLE patients did not differ from that of the controls.

Some characteristics of RA patients with and without side effects due to gold treatment.

Gold treatment was initiated in 98 patients suffering from early-stage rheumatoid arthritis. In 30 patients side effects due to gold therapy were seen during the first follow-up year: proteinuria in 6, allergic symptoms in 23, and thrombocytopaenia in one patient. The serum IgM level was higher in patients with side effects. None of the 33 other parameters studied showed any significant differences between patients with or without side effects.