Lubetkin Erica I, Jia Haomiao
Department of Community Health and Social Medicine, CUNY School of Medicine, New York, New York, USA.
Department of Biostatistics, Mailman School of Public Health and School of Nursing, Columbia University, New York, New York, USA.
BMJ Open. 2017 Jan 16;7(1):e013720. doi: 10.1136/bmjopen-2016-013720.
Persons aged 65 years and older represent a heterogeneous group whose prevalence in the USA is expected to markedly increase. Few investigations have examined the total burden of disease attributable to lower levels of income in a single number that accounts for morbidity and mortality.
We ascertained respondents' health-related quality of life (HRQOL) scores and mortality status from the 2003 to 2004, 2005 to 2006, 2007 to 2008 and 2009 to 2010 cohorts of the National Health and Nutrition Examination Survey (NHANES) with mortality follow-up through 31 December 2011. A mapping algorithm based on respondents' age and answers to the 4 core Healthy Days questions was used to obtain values of a preference-based measure of HRQOL, the EuroQol five dimensions questionnaire (EQ-5D) index, which enables quality-adjusted life years (QALYs) to be calculated. We included only respondents aged 65 years and older at the baseline, yielding a total sample size of 4952. We estimated mean QALYs according to different categories of income based on the percentage of Federal Poverty Level (FPL).
After adjusting for age, gender and education, the remaining QALYs decreased with each successive decrement of category of income, ranging from 18.4 QALY (≥500% FPL) to 8.6 QALY (<100% FPL). Compared with participants with a mean income of ≥250% FPL, participants with an income <250% FPL had significant losses in QALY for most of the sociodemographic groups examined. In contrast, persons with a lower educational attainment did not show a corresponding loss in QALY according to income category.
This study confirmed the association between lower income category and greater burden of disease, as measured by QALYs lost, among the US population aged 65 years and older. Our findings provide additional evidence of the role played by other key determinants of health and how factors not traditionally addressed by the healthcare system impact the life cycle of individuals and communities.
65岁及以上的人群是一个异质性群体，预计其在美国的患病率将显著上升。很少有研究以一个综合考虑发病率和死亡率的单一数字来考察因收入水平较低导致的疾病总负担。
我们从2003至2004年、2005至2006年、2007至2008年以及2009至2010年的美国国家健康与营养检查调查（NHANES）队列中确定了受访者的健康相关生活质量（HRQOL）得分和死亡状况，并对其进行随访直至2011年12月31日。基于受访者的年龄以及对4个核心健康日问题的回答，使用一种映射算法来获取基于偏好的HRQOL测量值，即欧洲五维健康量表（EQ - 5D）指数，该指数可用于计算质量调整生命年（QALY）。我们仅纳入基线时年龄在65岁及以上的受访者，最终样本量为4952人。我们根据基于联邦贫困水平（FPL）百分比划分的不同收入类别来估计平均QALY。
在对年龄、性别和教育程度进行调整后，随着收入类别连续递减，剩余的QALY随之减少，范围从18.4 QALY（≥500% FPL）到8.6 QALY（<100% FPL）。与平均收入≥250% FPL的参与者相比，收入<250% FPL的参与者在大多数所考察的社会人口学群体中，QALY均有显著损失。相比之下，受教育程度较低的人群并未根据收入类别表现出相应的QALY损失。
本研究证实了在美国65岁及以上人群中，较低的收入类别与以损失的QALY衡量的更大疾病负担之间存在关联。我们的研究结果为健康的其他关键决定因素所起的作用以及医疗保健系统传统上未涉及的因素如何影响个人和社区的生命周期提供了更多证据。
