Mark Harrison, Manchester Centre for Health Economics, University of Manchester
Matt Sutton, Manchester Centre for Health Economics, University of Manchester
Corresponding author:Silviya Nikolova, Academic Unit of Health Economics, Leeds Institute of Health Sciences, Charles Thackrah Building, University of Leeds, 101 Clarendon Road, Leeds, LS2 9LJ, Telephone: 0113-343-0578, Email: firstname.lastname@example.org
Funding: This work was funded by a MRC Methodology Research Programme Grant, G0901491 “Attribution of patient reported outcomes to the effects of care providers”.
Conflict of interest disclosure:None of the authors have any conflict of interests to declare.
Reducing waiting times has been a major focus of the English National Health Service (NHS) for many years but little is known about the impact on health outcomes. The collection of data on Patient Reported Outcome Measures (PROMs) for all patients undergoing four large-volume procedures facilitates analysis of the impact of waiting times on patient outcomes. The availability of PROMs before and after surgery allows us to estimate the impact of waiting times on the effectiveness of treatment, controlling for pre-surgery health and the endogeneity of waiting times caused by prioritisation with respect to pre-intervention health. We find that waiting time has a negative and statistically significant impact on the health gain from hip and knee replacement surgery and no impact on the effectiveness of varicose vein and hernia surgery. The magnitude of this effect at patient level is small, 0.1% of the outcome measure range for each additional week of waiting. However, the value of this effect is substantially larger than existing estimates of the disutility experienced during the waiting period. The health losses associated with an additional week of waiting for annual populations of hip and knee replacement patients are worth £11.1 million and £11.5 million respectively.
Between 1997 and 2009, the English Department of Health virtually eliminated the very long waiting times that some patients experienced for elective treatments (Smith & Sutton, 2013). The main explanation was likely to have been the adoption of a “targets and terror” regime, comprising highly-publicised maximum waiting time limits which were rigorously monitored and accompanied by strict sanctioning of managers for under-performance. Maximum waiting times for elective treatments were reduced from over 18 months to 18 weeks with little evidence of negative side-effects (Propper, et al., 2010). However, this regime was also supported by a substantial increase in resources, encouragement of patient choice of provider, increased competition and provider diversity, and reformed provider payment methods (Smith & Sutton, 2013). In 2009, a new set of patient entitlements were published in the form of an ‘NHS Constitution’. This formalised the right to treatment within 18 weeks of first referral from a general practitioner unless cancer is suspected, in which case patients have the right to see a specialist within two weeks.
Waiting times play a critical role in the management of public health systems by managing and prioritising demand (Borowitz, et al., 2013). However, waiting for treatment can also be associated with a loss of social welfare for three reasons (Cullis, et al., 2000) (Koopmanschap, et al., 2005). First, benefits received now are worth more than those received later because of time preference. Second, individuals on a waiting list can be expected to be in less good health whilst on the waiting list than after treatment. Third, waiting for treatment can affect the effectiveness or health gain of an intervention such as surgery. (Propper, 1995) estimated the disutility of time spent on a waiting list, which may relate to either or both of the first two reasons, to be £50 per patient per month at 1991 prices by measuring the population’s willingness-to-pay for a shorter wait. However it is unlikely that this estimate includes consideration of any long term health impacts of waiting.
Findings of the impact of waiting time on outcomes in the urgent surgical context of coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA) for coronary artery disease (Sari et al., 2007; Légaré et al., 2005; Sampalis et al., 2001; Koch et al., 1997) seem to point to detrimental effects for longer pre-operative waits. Two studies comparing outcomes for people who underwent a CABG with varying degrees of urgency ranging from urgent (immediate) to semi-urgent (median 52 days) found no difference between groups in mortality or morbidity (major adverse cardiac events, prolonged intensive care treatment) after attempting to control for patient characteristics which influence the length of waiting and outcomes (Sari et al., 2007; Légaré et al., 2005). Conversely, other studies report associations of poorer pre-operative SF-36 domain scores, higher rates of post-operative adverse events, an increased likelihood of not returning to work (Sampalis et al., 2001), and a lower success rate of PTCA (Koch et al., 1997). Associations of poorer outcomes with longer waits were found in the studies considering longer waiting times of 12 weeks or more (Koch et al., 1997) or greater than 97 days (Sampalis et al., 2001).
The existing evidence of the impact of waiting time on health outcomes for less urgent treatment is less conclusive. Randomised controlled trials of alternative scheduling of rheumatology appointments (Hurst, et al., 2000) or joint replacement (Tuominen, et al., 2010; Hirvonen, et al., 2007; Hirvonen et al., 2007) show that longer waiting time for treatment is not associated with poorer health status at admission, nor poorer post-treatment outcomes. Findings from studies using observational data are more equivocal. A number of studies of joint replacement have found that waiting longer for treatment is associated with poorer pre-treatment health status (Noseworthy, et al., 2005; Fielden et al., 2005), which in turn is associated with poorer post-treatment outcomes (Noseworthy, et al., 2005; Garbuz, et al., 2006; Ostendorf et al., 2004; Desmeules et al., 2012; Desmeules et al., 2010). While patients with poorer pre-treatment health status may gain more from treatment, post-treatment health status remains lower than those who received treatment more quickly (Hajat, et al., 2002; Fielden et al., 2005). Similarly, studies of patients waiting for varicose vein surgery found evidence of significant deterioration in both pre- (Kelly et al., 2001) and post-treatment outcomes (Sarin, et al., 1993). Although these conclusions are supported by findings in other clinical areas, for example chronic pain (Lynch, et al., 2008), other studies of joint replacement (Escobar, et al., 2009; Brealey et al., 2012), varicose veins, inguinal hernia and gallstones (Oudhoff, et al., 2007) find no association between waiting times and outcomes, though anxiety may increase with length of waiting time (Oudhoff, et al., 2007).
The reasons for the conflicting evidence are unclear. The randomised controlled trials have focused on comparing routine waiting times with faster access to treatment. In these studies, fast access ranged from 1 to 3 months (Hurst, et al., 2000; Tuominen, et al., 2010) whilst routine waiting times ranged from 3 to 8 months (Hurst, et al., 2000; Tuominen, et al., 2010). In contrast, the observational studies that find significant, negative impacts of waiting time on outcomes arise from long waits, typically of 6-12 months or longer (Noseworthy, et al., 2005; Hajat, et al., 2002; Sarin, et al., 1993). It is possible that the waiting times in the randomised controlled trials were not sufficiently long to influence pre-treatment health or post-treatment outcomes.
The trials also exclude high proportions of eligible participants for refusing consent, limiting the generalizability of results. In addition, there was overlap in waiting times in faster access (intervention) and routine (control) groups which may dilute any difference in outcome. However, observational studies have either been limited by small sample sizes (Noseworthy, et al., 2005; Garbuz, et al., 2006; Oudhoff, et al., 2007), a limited set of covariates to control for confounders which may affect both waiting times and outcomes (Garbuz, et al., 2006), or reliance on waiting times reported by patients (Hajat, et al., 2002).
One further potential explanation is the outcome measures used to estimate the impact on health. The randomised controlled trials used generic health-related quality of life measures (Tuominen, et al., 2010; Hurst, et al., 2000; Hirvonen, et al., 2007) whereas observational studies have used more disease-specific measures of function (Noseworthy, et al., 2005; Hajat, et al., 2002) which may be more sensitive to specific symptoms.
There are currently no estimates of the value of the long-term impacts of waiting for surgery on post-surgery health. Since 2009, providers of elective surgery funded by the NHS in England have been required to collect and submit Patient Reported Outcome Measures (PROMs) for patients undergoing four large-volume procedures: hip replacement; knee replacement; inguinal hernia; and varicose veins. We use this large and rich dataset to provide new evidence on how waiting times affect outcomes. By using a large database with pre- and post-intervention generic and disease specific measures collected on all patients in England, our analysis improves upon the previous literature. We are also able to control for a broad set of covariates which may affect waiting times and/or health outcomes. We focus our interest on the two generic measures of health-related quality of life, the EQ-5D index and EQ-VAS, and a disease-specific measure for three of the four procedures, the Oxford Hip Score, the Oxford Knee Score and the Aberdeen Varicose Vein Score. We also examine reported satisfaction with the procedure post-surgery, patient perceptions of the success of the intervention, and self-assessed general health.