INTRODUCTION

Psoriasis is a chronic dermatology disease that affects 1-3% of the world’s population (Colombo et al. 2008; Stern et al. 2004). The majority of the patients reported that the disease had a moderate to great negative impact on their quality of life and poses great economy burden (Augustin et al. 2008; Tang et al. 2013). Treatment available for psoriasis patients include topical, phototherapy, systemic and biologic. Treatment is based on the severity of the illness (mild, moderate, or severe). Topical treatment is given to patients with mild severity while phototherapy treatment is administered to moderate to severe cases of psoriasis (who have failed the topical treatments) before starting them on systemic and biologics (Ministry of Health 2013; Morrow 2006; Schmitt & Ford 2006). Therapy options have a substantial effects on the overall costs related to psoriasis (Pearce et al. 2006; Steinke et al. 2013). Annual costs associated with psoriasis treatment modalities was up to RM42 billion (€7 billion) in Germany and up to RM58 billion (US$11 billion) in the United States (Morrow 2006; Schmitt & Ford, 2006). As the management for psoriasis evolve from inpatient to outpatient care, many patients would need lifelong care and expensive treatments such as systemic and biologic (Pearce et al. 2006). At a tertiary care level, the cost could increase up to 20 times more due to the different interventions used (Ferrándiz et al. 2010; Raho et al. 2012). Comorbidities such as cardiovascular disease and depression, that are associated with psoriasis patients, may escalate the treatment costs (Mustonen et al. 2014). 

Biologics have revolutionised the management of psoriasis. However, greater cost associated with biologic medication might hinder its use in clinical settings (Chen et al. 2014; Mantovani et al. 2016; Vañó-Galván et al. 2012). In the light of shrinking health and care budget combined with limited health care resources, treatment regiments should be evaluated in relative to their cost and effectiveness (Ellis & Barker 2000). There is not much research on the cost of treatment for psoriasis in this region. Therefore, this study aimed at estimating the costs associated with four different psoriasis treatment in Malaysian public hospitals. 

METHODOLOGY 

This was a prospective cohort study to evaluate the cost of four psoriasis treatments i.e. topical; topical and phototherapy; topical and systemic; topical and biologic, at four public hospitals, namely Hospital Kuala Lumpur (HKL), Hospital Sultanah Aminah Johor Bahru (HSAJB), Hospital Sultanah Bahiyah (HSB), Hospital Pulau Pinang (HPP) and the Universiti Kebangsaan Malaysia Medical Centre. Respondents were moderate to severe psoriasis patients attending the Dermatology Clinic at these hospitals from November 2015 until March 2017. The selection of the respondents in this study was based on the criteria as illustrated in Sulong et al. (2016). 

A cost analysis was conducted from a societal perspective. Components of the costs borne by the provider include capital cost (building cost), recurrent cost (emolument, consumables, utilities and maintenance) and direct costs (medication, laboratory investigation and radiological examination). Costing methods in this study was as per description by Sulong et al. (2016). Various components of the provider’s cost were shared with other services provided by the hospitals. Hence, the allocation method was used based on the ratio of psoriasis patients as inpatients (number of days) and ratio of psoriasis patients as outpatients to the clinic per year (Sharifa Ezat et al. 2009) (Table 1). 

RESULTS 

A total of 91 patients were recruited for this study. Demography of the majority of the patients were as follows: males (56[62%]), aged more than 35 years old (58[63%]), Malays (61[67%]), higher education (33[35%], married (62[68%]) and employed (85[93%]) with income between RM0-3000.00 (49[54%]). Majority of the patients received topical and systemic treatment (40[44%]), followed by topical (32[35%]), topical and biologic (10[11%]) and topical and phototherapy (9[10%] (Table 2). 

Table 3 shows the estimated cost of treatment of psoriasis for six months duration. Cost of treating psoriasis in this cohort was RM706,416.00 with cost per patient at RM7,762.81. Medication exhibited the highest cost which was almost 90% of the total provider cost (RM457,014.00; cost per patient was RM5,022.13) followed by laboratory tests (RM49,329.00; cost per patient was RM542.08) and radiology (RM1,744.00; cost per patient was RM19.16). From the patient’s perspective, loss of productivity was the greatest cost (RM167,448.00; cost per patient was RM1,840.09), followed by out of pocket payments (RM20,610.00; cost per patient was RM226.48) and travelling cost (RM10,271.00; cost per patient was RM112.87). Table 4 shows inpatient and outpatient costs. It was estimated that cost per patient per day for inpatients was RM1,105.24 and cost per patient per visit for outpatients was RM298.02. There was a significant difference across the group in all modalities for provider’s and patient’s costs (p<0.05). From provider's perspective, topical and biologic exhibited greatest medication cost, with RM333,295.00, meanwhile, topical and systemic yielded highest lab test and radiology test with RM26,565.00 and RM850.00 respectively. From patient's perspective, topical and phototherapy produced highest productivity cost with RM73,170.00, while topical and systemic produced greatest traveling cost with RM3960.00. On the other hand, topical incurred highest out of pocket payments with RM8,430.00 (Table 5).

DISCUSSION 

In this study, the cost estimation for treating psoriasis in this cohort (6 months follow-up) was RM706,416.00 with cost per patient at RM7,762.81. A previous study conducted by Tang et al. (2013) showed that the estimated cost of the treatment of psoriasis was RM1,307.47/person/year (year 2007). The number of participants, severity of the illness, component of costs, and the principle of costing might explain the difference in costs. All respondents in this study had moderate to severe psoriasis, which has been proven to impose greater economic burden than mild psoriasis (Balogh et al. 2014; Gospodarevskaya et al. 2009; Sohn et al. 2006; Steinke et al. 2013). In addition, inflation could be another cause for the greater costs estimated in this study. This study utilised micro costing, ABC which provides the most precise cost estimation than macro costing (Drummond et al. 2015).

The cost of the treatment of psoriasis is well studied (Colombo et al. 2008; Crown et al. 2004; Mustonen et al. 2014; Balogh et al. 2014). However, the evidence concerning the economic impact of the treatment of psoriasis is limited in this region. In the USA, the cost of treating psoriasis was RM28,628.00 (US$6,422.00) patient/year (Vanderpuye-Orgle et al. 2015). A study conducted by Levy et al. (2012) showed that the annual cost for treating psoriasis in Canada was RM5.9 billion (US$1.7 billion) with cost per patient reported to be RM28,070.00 (US$7999.00). In Germany, Steinke et al. (2013) revealed that yearly costs per patient added up to RM38,844.34 (€7,092.00). In a systematic review, Obradors et al. (2014) discovered that the annual total cost of the treatment of psoriasis in Europe (from the social perspective) was between RM6,349.00 (€1,340.00) and RM39,104.00 (€8,253.00). Because our health care system is heavily subsidised, the estimated costs of the treatment of psoriasis are far lower than other countries. In addition, the use of expensive drugs such as biologics is still limited in this country which explains the lower cost of the treatment to psoriasis in this cohort compared to other countries (Tang et al. 2013). 

Our findings showed that medication appeared to be most significant aspects (90%) and this is in line with previous analysis conducted in European countries (Beyer & Wolverton 2010; Obradors et al. 2014). Productivity loss is not uncommon among psoriasis patients.  In fact, it surpasses the aspect of direct costs among patients with psoriasis (Raho et al. 2012; Schmitt & Ford 2006), approved the greatest cost. Generally, about 15% to 60% of workers with psoriasis  are absent from  work with an average of 26 days/year (De Arruda & De Moraes 2001; Mattila et al. 2013). In Taiwan, the cost due to reduced productivity accounted for 30-50% of the total expenses (Chen et al., 2014). 

Biologics and systemic treatments have higher cost due to medication and monitoring costs. This is especially relevant as systemic agents such as methotrexate, acitretin and cyclosporine have significant side-effects and cumulative toxicity. Therefore, laboratory tests need to be conducted to identify those who are at risk at developing toxicity (Ministry of Health, 2013). The price for systemic and biologic drugs are more costly compared to traditional therapies (Beyer & Wolverton, 2010). The estimated annual cost of biologic treatment varied from RM160,654.00 ($36,038.00) (adalimumab) to RM200,267.00 (US$44,924) (ustekinumab) in the year 2013 (Cheng & Feldman, 2014). 

Phototherapy is indicated for patients with moderate psoriasis where topical treatment has failed (Ministry of Health 2013). In this analysis, there is a smaller number of patients receiving this treatment. The possible explanation for this is because patients find it challenging to attend the clinic for phototherapy sessions for two (2) or three (3) days a week as they have to miss work which subsequently affects their income. It also requires many resources from the provider (Mustonen et al. 2014). In terms of cost, phototherapy has the least cost and the possible explanation for this is because of the lower number of patients receiving this modality in our analysis. Phototherapy may result in economic burden to patients and the provider. In a study conducted by Langan et al. (2004), it was found that the yearly cost of narrowband UVB was RM306,906.00 (€53,555.00) in Ireland with a mean cost per patient at RM1,862.00 (€325). Staffing was the most significant aspect, accounting for 70% of the cost. Recent evidence suggested that annual cost of narrowband UVB phototherapy at RM8,218.00 (US$1,734.00) was lesser than other treatment modalities: RM20,073.00 (US$4,235.00) for PUVA, RM36,818.00 (US$7,768.00) for cyclosporin, RM43,430.00 ($9,163.00) for acitretin, RM111,565.00 (US$23,538.00) for adalimumab, RM112,043.00 (US$23,639.00) for infliximab, RM115,835.00 (US$24,439.00) for eanercept except for methotrexate, at RM5,673.00 (US$1197.00) (Beyer & Wolverton 2010). 

A major strength of our study was that this was the first study conducted in Malaysia to estimate the cost of treatment for psoriasis and hence, it was able to provide important input to policy makers in the allocation of resources. This is a comprehensive economic evaluation which includes all available treatment modalities and costs that were evaluated from both perspectives (provider and patient). A Clinical Pathway (CP) for moderate to severe psoriasis patients was specifically developed for the data collection in this study. Due to the detailed care plan (illustrated in the CP), true estimation of cost in each activity of treatment (Ismail et al. 2016) was provided. The main limitation of this study was short time horizon. Psoriasis is a long-term disease and its treatment lasts for lifetime, therefore, it would be ideal for an economic evaluation to measure costs associated with the changes and interruptions during treatment for many years. In addition, cost of side effects and comorbidities were excluded in the analysis. These factors could influence overall cost of the treatments.   

CONCLUSION

Our study showed that patients receiving the topical along with biologic treatment incur an overall highest cost compared to other classic interventions when prescribed in an outpatient setting. Understanding the relationship between direct and indirect costs from both perspectives is necessary to accurately identify and evaluate effective treatments for psoriasis. 

ACKNOWLEDGEMENT

This study was funded under Research University Grant (Project ID: GUP-2014-055). Approval was obtained from the Research and Ethic Committee of Universiti Kebangsaan Malaysia Medical Centre (UKMMC) and National Medical Research Registry (NMRR). The authors would like to express appreciation to the Dermatology Consultants for their input during the conception of the study, as well as the patients who participated in this study.