Proceso de Control

All the analyses presented (including MWTP, Value functions and associated uptake rates, and Compensating Variation) serve to illustrate that patients’ valuation of

community or hospital based DVT function is inextricably related to the extent to which the different types of provision deliver a bundle of DVT service attributes that patients value. Our findings cannot simply be used to support the view that either community or hospital based DVT provision is inevitably better. This means that our findings need to be

considered alongside a range of clinical considerations when deciding what type of DVT provision ought to be delivered.

Recent advancements in drug treatment both for prophylaxis and treatment of DVT (Ageno and Turpie 2005; Cohen, Hirst et al. 2005; Gutt, Oniu et al. 2005; Petersen 2005; Stannard, Lopez-Ben et al. 2006) may serve to increase the trend away from inpatient based treatment of DVT / suspected DVT. This makes consideration of whether care should be provided in hospital outpatient departments or the community an important

129 issue. In terms of heparin treatment, the findings of a Cochrane review of evidence in this area concluded that home treatment is no more susceptible to complications than hospital treatment. This led the reviewers to tentatively conclude that the limited evidence

available indicates that home management is cost effective and (they suggested) likely to be preferred by patients (Schraibman, Milne et al. 2007).

Evidence from a well-designed Canadian economic evaluation (O'Brien, Levine et al. 1999) also supports the view that home based treatment with low molecular weight heparin is less expensive than inpatient treatment. Moreover, clinical outcomes and patient quality of life were not compromised. A more recent Spanish study (Montes, Gonzalez et al. 2005) comparing community with inpatient provision reaches the bolder conclusion that even for patients with “serious conditions” DVT management can be safely undertaken in the home and on a cost-saving basis via a home care unit.

A variety of approaches (in addition to the discrete choice experiment approach used in this study) could be adopted in order to elicit preference information. These include patient satisfaction surveys (Cohen, Forbes et al. 1996; Castle, Brown et al. 2005). However a limitation of this approach is the somewhat nebulous concept of ‘patient satisfaction’ (Williams 1994). Citizens’ juries have also been used to obtain information on preferences (Mossialos and King 1999; Mooney and Blackwell 2004). Protagonists of citizens’ juries suggest they allow for debate and reflection such that the preferences are better informed (Dolan, Cookson et al. 1999). However, opponents of this approach argue that empirical evidence indicates that juries are “chiefly concerned with non-rational persuasion, and because of this they are morally and democratically irrelevant.” (Price 2000). By

implication, therefore, far from helping to form more rounded preferences citizens’ juries could serve to pervert them. Focus groups have also been used to obtain information on preferences (Bowie, Richardson et al. 1995; Bradley, Sweeney et al. 1999; Shaffer, Yebei et al. 2006). However, there is uncertainty about the optimal size of groups, or indeed

130 whether there is an optimal size, and what factors should determine this (Tang and Davis 1995). Focus groups may also be subject to the sort of criticisms made against citizens’ juries (Price 2000), especially if the ‘framing’ of questions posed can sway the parameters of the debate.

Patient preferences are clearly important when considering new service models (Ryan, Scott et al. 2001; Jones, Berney et al. 2004) Although there is some information on patient preferences (Rodger, Gagne-Rodger et al. 2003), there remains a paucity of information on preferences for different models of healthcare provision. This analysis helps to bridge this gap, using DCEs to place monetary valuations upon characteristics of provision. Our analysis illustrates that both factors affecting health outcomes (e.g. speed of imaging diagnosis) and also factors which mainly affect the nature of the ‘process’ of care (e.g. continuity of care; hours of available provision; and the number of times patients have to go to hospital) are of importance to DVT patients. Moreover, respondents have clearly demonstrated a willingness to trade between differences in these attributes.

One of the implications of these findings is that studies which currently seek to establish whether patients prefer hospital outpatient care or community home based care (by simply comparing the two models) may miss a crucial point. Our DCE results, interpreted using a variety of approaches including estimates of Willingness to Pay (WTP) using marginal willingness to pay figures (MWTP), uptake rates, and compensating variation (CV), suggest that patient preferences for one model or the other are intimately related to the extent to which either model performs in terms of attributes that are considered important by the patient. Therefore, applying a mainstream WTP analysis which does not value the different attributes of hospital or community based provision would miss this crucial point, which the present study helps to draw attention to. Thus, patients’ valuations may be related more to the degree to which prompt diagnosis or continuity of care can be provided by a model, rather than to whether or not the DVT service is provided in a

131 hospital or the community. It should be noted that in Leicester it was not common practice to use delayed repeat ultrasound scanning, so it made sense to include speed of

diagnosis. However, delayed repeat ultrasound is standard practice in many protocols (Goodacre, Sampson et al. 2006) and is particularly relevant for below the knee DVT. The findings therefore, in relation to respondent valuation of quicker diagnosis, cannot be generalized to patients who are, or ought to be given, delayed repeat ultrasound on clinical grounds.