QALY and DALY Measures (PDF)

QALY DALY etc. MEASURES ▪ Prof. Dr. Haydar SUR QALY and DALY ▪ QALY and DALY measure less than “excellent” health. ▪ This can be a measure of disability (DALY) or a measure of quality (QALY). ▪ See the perpendicular position of QALY and DALY in the next image. Haydar Sur P...

QALY DALY etc. MEASURES ▪ Prof. Dr. Haydar SUR QALY and DALY ▪ QALY and DALY measure less than “excellent” health. ▪ This can be a measure of disability (DALY) or a measure of quality (QALY). ▪ See the perpendicular position of QALY and DALY in the next image. Haydar Sur Presentation 2 Haydar Sur Presentation 3 QALY ▪ A chronic illness (such as schizophrenia) that has a severe negative impact on quality of life, for example, will achieve a disability score of 0.8 ▪ [0 represents excellent health – 1 death]. ▪ This will also indicate a level of 0.2 in the quality of life score. ▪ [0 represents death - 1 represents excellent health]. Haydar Sur Presentation 4 ▪ 1 year of life in full health equals 1 QALY. ▪ Death means going down to 0 QALY. ▪ ▪ QALY is a criterion by which health- related quality is calculated together for different periods of life. Haydar Sur Presentation 5 DALY ▪ It is obtained by calculating the years of life with disability (YLD) or the years of life lost (YLL). ▪ ▪ YLL is based on the gender and age specific line of a standard human life, "if there was no death, how many years would life continue with which functions?" calculated based on the question. ▪ ▪ YLD, on the other hand, is the product of the severity of the disability and the time lived with this disability. Haydar Sur Presentation 6  CASE STUDY ▪ Let's say a 60-year-old person has a heart attack for the first time after a perfectly healthy life. The normal life expectancy is expected to be 80 years. ▪ This person goes to the health institution with the crisis and escapes death. If this health service was not provided, this person would have been killed by a heart attack at the age of 60. Now she's starting to live a little bit of her perfect health – taking heart pills and not doing things, being mindful of what she eats and being prepared for a second heart attack. ▪ Let's say this state of health corresponds to 0.9 on the standard health chart (90% of normal on the QALY chart). In the DALY chart, its equivalent is 0.1. At the age of 70, a person dies of a second heart Haydar Sur Presentation 7 attack. CASE SOLUTION Years lost due to heart attack are as follows: ▪ Lost ( DALY)= YLL (80 – 70) + YLD ( 10 * 0.1) = 11 DALY. ▪ QALY from medical intervention after the first heart attack: ▪ 10 yıl * 0.9 = 9 QALY ▪ Note that the sum of these QALYs and DALYs corresponds to the remaining time between the ages of 60 and 80. (11 + 9 = 20). Haydar Sur Presentation 8 QALY  DALY reduction ▪ If the cost of a medical intervention is to be compared with the gains, the QALY gain due to the intervention and the reduction of the DALY (loss) due to the intervention will yield similar values. ▪ ▪ In our example, the QALY gain was 9. What is the DALY reduction degree of the intervention whose cost effectiveness will be measured? If there was no intervention, the person would have died in the first heart attack and 20 DALYs would have been occured. The DALY prevented by intervention was 11 (the DALY reduced by the intervention). Haydar Sur Presentation 9 SCALES ▪ The QALY and DALY scales range from 0 to 1. However, the calculation of these criteria is the expression of this simple logic with some complex mathematical formulas. Haydar Sur Presentation 10 Haydar Sur Presentation 11 Haydar Sur Presentation 12 OTHER MEASURES ▪ Health-adjusted life-expectancy (HALE). ▪ It is the calculation of health expectancy with the logic of equivalence to perfect health with a simple index. These calculations are useful for estimating health expectancy (1 perfect health level) with very different details. ▪ Disability-adjusted life-expectancy (DALE). ▪ It is a variant of HALE. In this species, it refers to the portion of perfectly healthy life years expected at birth lost due to disability. ▪ Disability-free life-expectancy (DFLE). ▪ It is a two-choice criterion. 0 means disability above a certain degree, 1 means Haydar Sur not. Presentation 13 OTHER MEASURES ▪ Active life expectancy (ALE). ▪ Like DFLE, ALE is also bi-option. But classification is made as active and inactive. ▪ Healthy year equivalent (HYE) ▪ It is a form of QALY. However, the criterion based on objective medical evaluation is not the state of health, but the perception of health. It evaluates according to the profile of a period when the person is comfortable and happy. Haydar Sur Presentation 14 Disability-adjusted life-year /DALY) (Yeti Yitimine Uyarlanmış Yaşam Yılları) Haydar Sur Presentation 15 Disability-adjusted life-year /DALY) Here; ▪ L = time lost due to premature death or disability ▪ r = discount rate ▪  = weighting function of age ▪ C = Age weighting correction coefficient ▪ D = weight of disability ▪ a = age at start Haydar Sur Presentation 16 Haydar Sur Presentation 17 Haydar Sur Presentation 18 Quality-adjusted life-year / QALY) ▪ It is the most widely used measure of health-related use studies. It was developed by economists, operations researchers, and psychologists in the 1960s. It was given its final shape in 1976. If cost- effectiveness rates are calculated by calculating QALY, this is called cost-utility analysis. ▪ QALY can be calculated for a single patient or for a subgroup. It is used to study different parts of life. ▪ Case-specific QALYs can be calculated, but there are problems when comparing them to each other. ▪ Case-specific QALYs can be calculated, but there are problems when comparing them to each other. Haydar Sur Presentation 19  QALY score tables ▪ QALY has been used to investigate the cost-effectiveness of certain interventions. ▪ In addition, “QALY score tables” are created by sorting the output of different interventions as QALYs. ▪ Countries have tended to make decisions by looking at the QALY outputs on whether or not to use some drugs. Haydar Sur Presentation 20 Example: QALY calculation ▪ Let's try to calculate the QALY for a woman who is expected to live 79 years at birth. (In the example, the calculation was made without discounts, because discounts complicate the calculations). ▪ The first 40 years of the woman passed in perfect health (no one is given a full 1, because minor health problems are always experienced) 0.95 score for this period. ▪ Between the ages of 40 and 60 (20 years) he is experiencing some wear and tear in his health. 0.90 score for this period. ▪ Between the ages of 60 and 70 (10 years) with other symptoms, the score drops to 0.80. ▪ New health problems are added between the ages of 70 and 82 (12 years). 0.70 Haydar score for this period. Sur Presentation 21 Example: QALY calculation ▪ Such a life adventure describes this woman's lifetime of 72.4 QALY. ▪ ( 40 x 0.95 + 20 x 0.9 + 10 x 0.8 + 12 x 0.7). ▪ If this woman had had successful hip joint surgery at the age of 60, the decline that would have occurred until the age of 70 would have been prevented and an extra QALY would have been gained. ▪ QALY (10 x (0.9 - 0.8)). Haydar Sur Presentation 22 Calculation of QALYs as a whole of the country ▪ Two rough approximations and generalizations are made here. ▪ 1 QALY earned by an older person is counted as 1 QALY earned by a younger person. ▪ For example, 0.50 QALY earned by one person and 0.25 QALY earned by 2 people are considered equal. Haydar Sur Presentation 23 ▪ For the QALY to be a fit-for-purpose index, universally accepted definitions of health status and interventions are required. ▪ According to the Von Neumann-Morgenstein Expected Utilization Theory produced for this purpose, a few more assumptions are necessary. Accordingly, the value of health status; it is constant regardless of how long it lasts, where and when it occurs, and other circumstances. ▪ At the same time, the health status of those who give the scores to be entered into the QALY account is assumed to be equal to each other. (Human misconceptions…) Haydar Sur Presentation 24 DALY ▪ DALY was developed in the 1990s with the cooperation of WHO and WB. The main purpose of this was to reveal the negative burdens of diseases and injuries on the health of countries according to disease classifications. ▪ Thus, based on these burdens, more accurate health policies and decisions would be produced. Haydar Sur Presentation 25 ▪ The DALY calculation is calculated in the “International Classification of Impairments, Disabilities and Handicaps” (0 perfect health, 1 represents death) indexed not to health, but to illness, disability and death. ▪ ▪ In the Global Burden of Disease approach, classification is made with 22 indicators related to health status. Haydar Sur Presentation 26 ▪ Thus, the burden of disease is calculated for all major diseases. In this approach, the healthy life lived in young age is considered to be worth more points than the healthy life lived in old age. Haydar Sur Presentation 27 DALY (Disability Adjusted Life Years) ▪ It is an absolute measure of health loss that counts the years lost due to early deaths and diseases and injuries that do not result in death but cause long- term loss of function. 1 DALY represents the loss of 1 healthy life year. Haydar Sur Presentation 28 DALY hesaplanması ▪ Let's calculate DALY on the lifeline of the woman in the QALY account. ▪ Let the ideal life expectancy at birth be 82.5 and the ideal life expectancy at the age of 60 be 84.83 in the environment where the woman with a life expectancy of 79 years at birth lives. Haydar Sur Presentation 29 ▪ Assume that he lives in full health until the age of 60 (0 disability score) ▪ Let osteoarthritis start at this age and get 0.158 disability score if not treated, and 0.108 score if treated. ▪ Let this situation occupy the remaining 24.83 years of your life irreversibly. ▪ The DALY loss due to this condition will be 3.9 if not treated. (24.83 * 0.158). If treated (24.83 x 0.108) there will be a loss of 2.68 DALYs. ▪ Diabetes can occur in addition to osteoarthritis. Coefficient of loss from diabetes (between 0.012 and 0.078). This is the second health condition that needs to be calculated in the same way. ▪ If this woman had died in hip surgery at the age of 60, 22.5 DALYs would have Haydar Sur been lost. (82.5 – 60). 30 Presentation Years of Life with Disability (YLD): ▪ It refers to years lived in non-ideal health conditions that do not lead to death. ▪ For example, if a person who lived to the age of 60 in full health loses the ability to walk in a traffic accident and lives in a wheelchair for 14 years and dies at the age of 74 (let the quality of life score of the wheelchair be 0.3, this means that he has lost 0.7 of the quality of life score; time 0.7 x 14 = 9.8 years lost) 9.8 YLD will be recorded for this person. Haydar Sur Presentation 31 Years Life Lost (YLL) ▪ It is expressed as years of life lost due to premature death. ▪ Life years lost are calculated as the average life expectancy at birth in that country – the person's age at death. ▪ For example, if the average life expectancy at birth in that country is 80 years, when the person dies at the age of 74, YLL = 6 QALY (80-74). Haydar Sur Presentation 32 DALY = YLL + YLD ▪ DALY = Mortality load + Morbidity load ▪ The QALY of the person in our example ▪ ▪ 9.8 (morbidity) + 6 mortality = 15.8. ▪ Instead of the expected 80 QALY at birth, this person will have completed his life by obtaining 80 -15.8 = 64.2 QALYs. Haydar Sur Presentation 33 2019 GLOBAL BURDEN OF DISEASE SURVEY ▪ 286 causes of death, 369 diseases and injury and 87 risk factors; ▪ It is a study carried out to measure the health profile and changes in the health profile at the national and global level by evaluating 204 countries. ▪ By University of Washington Institute for Health Metrics and Evaluation (IHME) Haydar Sur Presentation 34 Disese Burden Studies ▪ It provides important information in determining priorities in health policies and evaluating the results of the programs carried out. ▪ The burden attributed to the burden and risk factors of premature deaths in countries and regions and diseases and injuries that do not result in death but lead to long-term disability are calculated. ▪ 2019 Burden of Disease Study ▪ It provides data at the level of gender, age group, year, country, region, disease and risk factors, allowing detailed comparisons with disease burden values. Haydar Sur Presentation 35 2019 Burden of Disease Survey ▪ Sex, age group, year, country, region, disease and risk factors levels data were provided ▪ It gives the possibility of detailed comparisons with disease burdens Haydar Sur Presentation 36 THANK YOU Haydar Sur Presentation 37