Evaluation Of Health Related Quality Of Life And Establishment Of Mathematical Mode For Treatment Decision-making In Chinese Patients With Rheumatic Diseases

Objectives: To investigate the construct and criterion validity of the Euro Qol-5D(EQ-5D),which allows quality-adjusted life years to be calculated,in patients with systemic lupus erythematosus(SLE).To explore whether the utility values obtained by direct or indirect methods are comparable and which approach is the most appropriate in Rheumatoid Arthritis(RA)and SLE.A mathematical model of moderate to severe RA was developed to analyse the cost-effectiveness of 6 competing treatment strategies from the perspective of Chinese society.Methods: 240 consecutive SLE patients were recruited.Cross-sectional correlations of the EQ-5D with equivalent domains in disease-specific health related quality of life(HRQo L),Lupus Qol,Systemic Lupus Erythematosus Disease Activity Index(SLEDAI)measures,the Systemic Lupus International Collaborating Clinics Damage Index(SDI),and patient characteristics were tested.Discriminant validity to assess the ability to distinguish between patients of different disease severity was assessed.There also were evaluations of ceiling and floor effects.We compared the utility values obtained by an indirect method(EQ-5D)with direct utility instruments,the standard gamble(SG),time trade-off(TTO),visual analog scale(VAS),in SLE and RA patients.Hypothetical cohorts with moderate to severe RA were simulated and the Markov model was developed by incorporating the clinical trial data and Chinese unit costs and treatment sequences from a lifetime perspective.Primary analysis included drug costs,monitoring costs,and other costs.Probabilistic and one-way sensitivity analyses were performed.Treatment sequences that included(1)low-dose prednisone in addition to the initial disease-modifying antirheumatic drug(DMARDs),(2)Nonsteroidal Antiinflammatory Drugs(NSAIDs)in addition to the initial DMARDs,(3)combination of another cs DMARDs,(4)anti-TNF in addition to the initial DMARDs(Etanercept,Infliximab,Adalimumab).Probabilistic and one-way sensitivity analyses were performed in the mathematical model.Results: The EQ-5D correlated moderately to strongly with all domains of the Lupus Qo L(r: 0.44–0.7)apart from intimate relationships(r = 0.179)and body image(r = 0.18).There was moderate negative correlation between EQ-5D and clinical assessment of disease,SLEDAI(r =-0.589)and SDI(r =-0.509).When compared with equivalent domains on Lupus Qo L,there was good construct validity in EQ-5D(r: 0.631-0.812).EQ-5D could also discriminate patients with varied disease severity(according SLEDAI and SDI).There was no floor effect in EQ-5D but the ceiling effect remains strong(34%).The correlations between VAS,EQ-5D and Lupus Qo L were significant in SLE;similar results were seen in RA.Relative good intraclass correlations or kappa coefficients indicated the reliability of these instruments in RA and SLE.A model incorporating the SLEDAI scores and Lupus Qo L domains of emotional health and pain was a good predictor of VAS.DAS28 and HAQ were a good predictor in the RA regression model.In comparison with low-dose prednisone in addition to the initial DMARDs,the incremental cost effectiveness ratios(ICERs)for etanercept,infliximab,and adalimumab?622653.41/QALYs?531872.30/ QALYs?612141.40/QALYs.No one was cost-effective under the willingness to pay threshold when the threshold was 3 times the per capita GDP of China compared with low-dose prednisone in addition to the initial DMARDs.Conclusion: Our results provide sufficient evidence that the EQ-5D displays construct and criterion validity for use in SLE patients.Disease-specific measures of HRQo L used alongside may be a better choice.The findings also suggested that the VAS,SG,TTO and EQ-5D might be valid and reliable measures to assess health related quality of life in SLE and RA patients and EQ-5D was recommended.Lowdose prednisone in addition to the initial DMARDs was the most cost-effective option to moderate to severe RA patients,who had refractory response to MTX,in the Chinese healthcare setting according to the results of RA mathematical model.