Essays on the longitudinal analysis of health and healthcare data

The central theme of this thesis is the longitudinal analysis of health and healthcare data. Chapter 2 uses the first wave of, and latest longitudinal follow-up to, the Health and Lifestyle Survey (HALS) to investigate the social gradient in cancer, considering both lifetime incidence and duration models of time-to-cancer -- healthy time lived before developing cancer. Contrary to previous claims regarding the relationship between circumstances and the development of cancer, such as Deaton (2002) and Wilkinson (2010), a social gradient in time-to-cancer is observed, with those in the lowest two social classes developing cancer approximately 15% sooner than individuals in the highest social class. This relationship holds after excluding smokers from the sample. No significant gradient is observed when only lifetime incidence of cancer is considered. Chapter 3 investigates the relationship between smoking and ill-health, with a focus on cancer outcomes. A discrete latent factor model for smoking and health outcomes, allowing for these to be commonly affected by unobserved factors, is jointly estimated, using the British Health and Lifestyle Survey (HALS) dataset. Post-estimation predictions suggest the reduction in time-to-cancer to be 5.7 years for those with a smoking exposure of 30 pack-years, compared to never-smokers. Estimation of posterior probabilities for class membership show that individuals in certain classes exhibit similar observables but highly divergent health outcomes, suggesting that unobserved factors in this model substantially determine these outcomes. The use of a joint model changes the results substantially. The results show that failure to account for unobserved heterogeneity leads to differences in survival times between those in different social classes and with different smoking exposures to be overestimated by more than 50% (males, with 30 pack-years of exposure). Chapter 4 uses Hospital Episode Statistics, English administrative data from the Department of Health, to further investigate the red herring thesis, as advanced by Zweifel (1999). We use a sample of over 100,000 individuals who used healthcare in the financial year 2005/06 and had died by the end of the financial year 2012/13. We use a panel structure to follow individuals over seven years of this administrative data, containing estimates of inpatient healthcare expenditures (HCE), information regarding individuals' age, time-to-death (TTD), and morbidities at the time of their admission. We find that, while TTD might better explain HCE than does age, TTD itself merely proxies for individuals' morbidities, and no longer explains differences in HCE once we condition on morbidities. Our results point to an important role for including estimates of future changes in morbidity when estimating future HCE

Health care expenditures, age, proximity to death and morbidity: implications for an ageing population

This paper uses Hospital Episode Statistics, English administrative data, to investigate the growth in admitted patient health care expenditures and the implications of an ageing population. We use two samples of around 40,000 individuals who a) used inpatient health care in the financial year 2005/06 and died by 2011/12 and b) died in 2011/12 and had some hospital utilisation since 2005/06. We use a panel structure to follow individuals over seven years of this administrative data, containing estimates of inpatient health care expenditures (HCE), information regarding individuals’ age, time-to-death (TTD), morbidities at the time of an admission, as well as the hospital provider, year and season of admission. We show that HCE if principally determined by proximity to death rather than age, and that proximity to death is itself a proxy for morbidity

Implications of non-marginal budgetary impacts in health technology assessment: a conceptual model

Objectives This paper introduces a framework with which to conceptualise the decision-making process in health technology assessment for new interventions with high budgetary impacts. In such circumstances, the use of a single threshold based on the marginal productivity of the health care system is inappropriate. The implications of this for potential partial implementation, horizontal equity and pharmaceutical pricing are illustrated using this framework. Results Under the condition of perfect divisibility and given an objective of maximising health, a large budgetary impact of a new treatment may imply that optimal implementation is partial rather than full, even at a given incremental cost-effectiveness ratio that would nevertheless mean the decision to accept the treatment in full would not lead to a net reduction in health. In a one-shot price-setting game, this seems to give rise to potential horizontal equity concerns. When the assumption of fixity of the ICER (arising from the assumed exogeneity of the manufacturer's price) is relaxed, it can be shown that the threat of partial implementation may be sufficient to give rise to an ICER at which cost the entire potential population is treated, maximising health at an increased level, and with no contravention of the horizontal equity principle

Health care expenditures, age, proximity to death and morbidity : implications for an ageing population

This paper uses Hospital Episode Statistics, English administrative data, to investigate the growth in admitted patient health care expenditures and the implications of an ageing population. We use two samples of around 40,000 individuals who (a) used inpatient health care in the financial year 2005/06 and died by the end of 2011/12 and (b) died in 2011/12 and had some hospital utilisation since 2005/06. We use a panel structure to follow individuals over seven years of this administrative data, containing estimates of inpatient health care expenditures (HCE), information regarding individuals’ age, time-to-death (TTD), morbidities at the time of an admission, as well as the hospital provider, year and season of admission. We show that HCE is principally determined by proximity to death rather than age, and that proximity to death is itself a proxy for morbidity

Pricing implications of non-marginal budgetary impacts in health technology assessment : a conceptual model

This paper introduces a framework by which to conceptualise the decision-making process in health technology assessment when the quantity of health forgone by acceptance is high enough such that the use of a single threshold based on the marginal productivity of the health care system is inappropriate, and draws out the implications of this for pharmaceutical pricing. Under the condition of perfect divisibility, a large budgetary impact of a new treatment may imply that optimal implementation may be partial rather than full, even at a given incremental cost effectiveness ratio (ICER) that would nevertheless mean the decision to accept the treatment in full would not lead to a net reduction in health. In a one-shot price setting game, this seems to give rise to horizontal equity concerns which may be more apparent than real. When the assumption of fixity of the ICER (arising from the assumed exogeneity of the manufacturer’s price) is relaxed, it can be shown that the threat of partial implementation may be sufficient to give rise to an ICER at which cost the entire potential population is treated, maximising health at an increased level, and with no contravention of the horizontal equity principle

Productivity of the English NHS : 2014/15 Update

This report updates the Centre for Health Economics’ time-series of National Health Service (NHS) productivity growth. The full productivity series runs from 1998/99, but this report updates the series to account for growth between 2013/14 and 2014/15, as well as looking at 10 year growth trends since 2004/05. NHS productivity is measured by comparing growth in the outputs produced by the NHS to growth in the inputs used to produce them. NHS outputs include the amount and quality of care provided to patients. Inputs include the number of doctors, nurses and support staff providing care, the equipment and clinical supplies used, and the hospitals and other premises where care is provided. The measure of NHS output captures all the activities undertaken for all NHS patients wherever they are treated in England. NHS output has increased between 2004/05 and 2014/15 primarily because ever more patients are receiving treatment. Compared to 2004/05, hospitals are treating 4.6 million (27%) more patients, while the number of outpatient attendances has increased by 19%. The output measure also accounts for changes in quality. On the upside, there have been year-on year improvements in hospital survival rates. On the downside, waiting times have been getting longer since 2009/10, although they remain shorter than they were in 2004/05. Taking account of the amount and quality of care, overall NHS output increased by 51% between 2004/05 and 2014/15. Output growth between 2013/14 and 2014/15 was 2.67%. Increased NHS output has come about in response to pronounced increases in NHS expenditure. This has funded both higher wages and more staff and resources. Wages rose by 19% between 2004/05 and 2014/15, while there was a 10% increase in the number of NHS staff. There has been increased use of agency staff, but there have been periods of retrenchment, notably whenever the hospital sector has been struggling to reduce deficits. The use of non-staff resources, such as equipment and supplies, has increased by virtually the same annual proportion (11%) year-on-year. Taken together, NHS inputs increased by 33% between 2004/05 and 2014/15. Input growth between 2013/14 and 2014/15 amounted to 1.78%. We calculate productivity growth by comparing output growth with input growth. Over the last decade NHS productivity has increased by 13.83% in total. Productivity growth has been especially strong since 2009/10, year-on-year growth averaging 1.75%. Growth between 2013/14 and 2014/15, as these latest figures show, amounted to 0.87%. This rate of NHS productivity growth since 2004/05 compares favourably with that achieved by the economy as a whole. Annual NHS productivity growth kept pace with that of the economy up to the recession in 2008/09. Since then NHS productivity growth has consistently outpaced that of the economy, which has stagnated

The impact of primary care incentive schemes on care home placements for people with dementia

Objectives: the interface between primary care and long-term care is complex. In the case of dementia, this interface may be influenced by incentives offered to GPs as part of the Quality and Outcomes Framework (QOF) to provide an annual review for patients with dementia. The hypothesis is that the annual reviews reduce the likelihood of admission to a care home by supporting the patient to live independently and by addressing carers’ needs for support. Study period: 2006/07 to 2015/16. Outcomes: admissions to a care home

A discrete latent factor model of smoking, cancer and mortality

This paper investigates the relationship between smoking and ill-health, with a focus on the onset of cancer. A discrete latent factor model for smoking and health outcomes, allowing for these to be commonly affected by unobserved factors, is jointly estimated, using the British Health and Lifestyle Survey (HALS) dataset. Post-estimation predictions suggest the reduction in time-to-cancer to be 5.7 years for those with an exposure of 30 pack-years, compared to never-smokers. Estimation of posterior probabilities for class membership shows that individuals in certain classes exhibit similar observables but highly divergent health outcomes, suggesting that unobserved factors influence outcomes. The use of a joint model changes the results substantially. The results show that failure to account for unobserved heterogeneity leads to differences in survival times between those with different smoking exposures to be overestimated by more than 50% (males, with 30 pack-years of exposure)