Abstract
This cross-sectional study examines trends in the prevalence of functional limitation in cancer survivors using data from the National Health Interview Survey.
Cancer and its treatment can lead to functional limitation, a key indicator of health associated with impaired quality of life and substantial economic burden.1,2 Although advances in diagnosis and treatment have improved cancer survival, whether progress has been made in reducing the burden of physical and social limitations among cancer survivors remains unclear. Thus, we examined 20-year trends in prevalence of self-reported functional limitations among US cancer survivors.
Methods
The National Health Interview Survey (NHIS) is a nationally representative cross-sectional survey of the US population. Our sample included adults in the 1999 to 2018 NHIS with self-reported history of cancer. Based on a conceptual model developed by Nagi3 and previous literature,4 functional limitation was defined as self-reported difficulty performing any of 12 routine physical or social activities without assistance (eg, difficulty sitting for more than 2 hours or difficulty participating in social activities). The eMethods in the Supplement presents survey question wording. Because the data were deidentified and publicly available, the study was deemed exempt by the Institutional Review Board at The University of Texas at Austin. This study followed the STROBE reporting guideline.
We examined trends in the number of prevalent cases of functional limitation. We computed the risk-adjusted period prevalence of functional limitation, using multivariable logistic regression to account for age, sex, self-reported race and ethnicity, education, insurance, income, survey year, region, cancer site, and time since diagnosis. We stratified the change in adjusted prevalence from 1999 to 2018 by clinicodemographic factors. Statistical testing was 2-sided (α = .05). We weighted estimates to account for NHIS's complex survey design. Data were analyzed in October 2022 using STATA version 17.0 (StataCorp).
Results
We identified 51 258 cancer survivors, representing a weighted population of approximately 178.8 million from 1999 to 2018. Most survivors were women (60.2%) and aged 65 years or older (55.4%). In 1999, 3.6 million weighted survivors reported functional limitation; this number increased to 8.2 million in 2018, a 2.25-fold increase. The number of limitation-free survivors increased 1.34-fold from 1999 to 2018 (Figure). For reference, the number of cancer-free individuals with functional limitation increased 1.6-fold during the same period.
Figure. Trends in the Number of Cancer Survivors Reporting Functional Limitation in the US, 1999 to 2018.
Values represent (A) the weighted number of cancer survivors in the National Health Interview Survey and (B) the number of survivors each year relative to those in 1999, stratified by those with and without a self-reported functional limitation. The fold increase value is given for each group. Error bars represent 95% CIs.
The adjusted prevalence of functional limitation among survivors increased from 57.0% in 1999 to 70.1% in 2018, a 13.1 percentage-point increase (95% CI, 12.5-13.6; P < .001 for trend). The change was greatest for Hispanic (25.1%) and Black survivors (19.4%), and those aged 55 to 64 years (17.2%) (Table).
Table. Trends in the Adjusted Prevalence of Functional Limitation Among Cancer Survivors in the US, 1999 to 2018.
| Characteristic | Sample, No. (weighted %) | Adjusted prevalence, % (95% CI)a | Absolute difference in adjusted prevalence, 1999-2018 (95% CI) | ||
|---|---|---|---|---|---|
| 1999-2018 (n = 51 258)b | 1999 (n = 2085)c | 2018 (n = 2940)d | |||
| All survivors | 51 258b | 64.5 (64.0 to 65.1) | 57.0 (54.4 to 59.7) | 70.1 (68.0 to 72.2) | 13.1 (12.5 to 13.6) |
| Age, y | |||||
| 18-44 | 5702 (11.0) | 49.9 (47.6 to 52.2) | 40.7 (31.2 to 50.2) | 55.1 (44.4 to 65.8) | 14.4 (13.2 to 15.6) |
| 45-54 | 6439 (12.5) | 65.0 (63.3 to 66.6) | 53.8 (45.6 to 62.0) | 68.0 (60.1 to 76.0) | 14.2 (14 to 14.5) |
| 55-64 | 10 762 (21.2) | 72.9 (71.7 to 74.1) | 59.4 (52.2 to 66.5) | 77.0 (72.6 to 81.3) | 17.6 (14.8 to 20.4) |
| 65-74 | 13 401 (25.6) | 56.2 (54.8 to 57.5) | 53.7 (47.7 to 59.8) | 63.1 (58.3 to 67.9) | 9.4 (8.1 to 10.6) |
| ≥75 | 14 954 (29.8) | 69.7 (68.4 to 71) | 67.2 (61 to 73.4) | 75.3 (71.1 to 79.5) | 8.1 (6.1 to 10.1) |
| Sex | |||||
| Female | 30 944 (60.2) | 67.7 (66.9 to 68.4) | 60.2 (56.3 to 64.1) | 74.3 (71.7 to 77.0) | 14.1 (12.9 to 15.4) |
| Male | 20 314 (39.8) | 59.5 (58.5 to 60.5) | 51.9 (46.8 to 57) | 63.3 (59.3 to 67.4) | 11.4 (10.4 to 12.5) |
| Race and ethnicity | |||||
| Black | 3994 (6.1) | 67.8 (65.9 to 69.7) | 57.0 (46.8 to 67.2) | 76.5 (69.2 to 83.7) | 19.5 (16.5 to 22.4) |
| Hispanic | 3109 (4.3) | 62.2 (59.8 to 64.7) | 39.7 (27.4 to 52.1) | 64.8 (54.8 to 74.9) | 25.1 (22.8 to 27.4) |
| White | 42 364 (86.7) | 64.4 (63.8 to 65.0) | 57.5 (54.7 to -60.3) | 70.0 (67.7 to 72.3) | 12.5 (12.0 to 13.0) |
| Othere | 1753 (3.0) | 64.2 (61.2 to 67.1) | 67.7 (58.4 to 76.9) | 68.7 (53.5 to 83.9) | 1.0 (−7.0 to 4.9) |
| Educational level | |||||
| Less than high school | 3324 (5.7) | 76.1 (74.3 to 78.0) | 76.5 (68.9 to 84.2) | 81.5 (71.8 to 91.3) | 5 (2.9 to 7.1) |
| High school or equivalent | 19 001 (36.8) | 68 (67.1 to 68.8) | 59.3 (55.6 to 63.0) | 74.2 (70.6 to 77.8) | 14.9 (14.8 to 15) |
| Greater than high school | 28 933 (57.5) | 60.9 (60.2 to 61.6) | 51.8 (47.8 to 55.7) | 67.2 (64.7 to 69.8) | 15.4 (14.1 to 16.9) |
Adjusted prevalence rates were estimated using a logistic regression model which included data from 1999-2018 and the following parameters: age, sex, race and ethnicity, educational attainment, insurance type, annual household income, survey year, census region, cancer type, time since cancer diagnosis, and the interaction term between each covariate and the survey year. Values for 1999 and 2018 represent the marginal effect size of the interaction term between each covariate and the specified year. Survey year, the interaction terms between each covariate and intermediate survey years (2000-2017), and covariates that were not statistically significant at P < .05 using 2-sided Wald F tests were omitted from the table for ease of interpretation.
Weighted number of survivors: 178 760 066 (95% CI, 175 723 253 to 181 796 879).
Weighted number of survivors: 6 463 684 (95% CI, 6 136 882-6 790 486).
Weighted number of survivors: 11 969 388 (95% CI, 11 303 209-12 635 567).
Includes Asian, American Indian, Alaska Native individuals, and participants with multiple races or restricted race availability. Asian, American Indian, and Alaska Native individuals were included in this category because of a relatively small sample.
During the study period, the adjusted prevalence of functional limitation was highest among survivors of pancreatic (80.3%) and lung (76.5%) cancers and lowest for survivors of melanoma (62.2%), breast (61.8%), and prostate (59.5%) cancers.
Discussion
The number of cancer survivors with self-reported functional limitation has more than doubled during the past 20 years, with relatively less growth in the number of limitation-free survivors. The 70% prevalence of functional limitation among survivors in 2018 is nearly twice that of the general population.4 These findings may reflect changes in treatment patterns for both early-stage cancers and late-stage cancers. We believe factors other than population aging are likely associated with increasing functional limitations, since survivors aged less than 65 years experienced the greatest increases. Study limitations include recall bias, lack of staging or treatment information, and subjective measurement of function.
Hispanic and Black survivors experienced a disproportionate increase in functional limitations during the study period, which could indicate improved access to cancer treatment and resultant functional limitations or decreased access to quality survivorship care. Variation in functional limitation by cancer site may indicate patterns of aggressive treatment for minimally curable disease (eg, pancreas) or increasing detection of lower-risk disease (eg, prostate). Given a growing population of cancer survivors, our findings suggest an urgent need for care teams to understand and address function,2,5 for researchers to evaluate function as a core outcome in trials,6 and for health systems and policy makers to reimagine survivorship care, recognizing the burden of cancer and its treatment on physical, psychosocial, and cognitive function.
eMethods. Survey Question Wording
Data Sharing Statement
References
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
eMethods. Survey Question Wording
Data Sharing Statement
