Underrepresentation of individuals 80 years of age and older in chronic disease clinical practice guidelines

Guideline selection

Recommendations for 5 dominant chronic conditions (diabetes, heart failure, hypertension, osteoporosis, and stroke) were analyzed, specifically 14 commonly used evidence-based chronic disease CPGs.^1–18 These chronic conditions were chosen because they affect a substantial percentage of older individuals, have an enormous effect on quality of life and Canadian health care costs, and have Canadian CPGs that are updated on a regular basis.

Descriptive analysis of all references published in the 14 guidelines was undertaken to determine the inclusion and representation of older individuals in the supporting evidence. The total number of references studied for each chronic disease was as follows: diabetes, N = 1883; hypertension, N = 299; heart failure, N = 750; osteoporosis, N = 600; stroke, N = 163. Of these, 2559 distinct research-based studies had human participants and were used as evidence for recommendations, 2272 of which included the mean ages of the study participants.

The 2008 diabetes,¹ 2002 osteoporosis,¹⁴ and 2006 stroke¹⁷ CPGs are comprehensive peer-reviewed guidelines that were produced to replace all previously published CPGs. These were reviewed along with any associated updates. Hypertension and heart failure CPGs are updated annually, with annual updates focusing on different treatment and management areas. Therefore, the hypertension and heart failure updates from 2009, 2008, 2007, and 2006 were also reviewed.^2–13 All references upon which recommendations from any of the 14 CPGs were based were included, with the understanding that some references were used as evidence for multiple recommendations both within the same CPGs and across different yearly updates.

Guideline assessment

Clinical practice guidelines were reviewed for age-specific recommendations, particularly for any identification or inclusion of frail older individuals, individuals older than 80 years of age, and individuals with multiple chronic conditions. Two sections of an instrument created by Boyd and colleagues²⁴ to assess American guidelines, and used for the assessment of Australian guidelines by Vitry and Zhang,²⁶ were adapted to assess the relevance of guidelines to the care of older people with multiple illnesses. Specifically, the “Issues Addressed” and “Recommendations” sections were expanded to distinguish between “younger” older individuals (65 to 79 years of age) and individuals in advanced old age (80 years of age or older).

Evidence assessment

All referenced articles used as justification for clinical recommendations in the 14 CPGs (ie, those that were research-based with human participants) were extracted and analyzed to examine the extent to which older individuals were included in the evidence-generating trials. The age data are presented in 2 ways. First, they are presented as the mean age plus 1 SD. We chose to use 1 SD because in a normal distribution, 84% of study participants would be below the mean age plus 1 SD. This percentage would be even greater if the age distribution were skewed in favour of younger participants as has been reported in recent reviews.^22–24 It is debatable what proportion of representation a specific subgroup needs to have for the results to be applied to that subgroup, but it is conceivable that a poor outcome in the relatively small number of old people could be swamped by a positive result in the younger age group. This is particularly important if there are physiologic differences that might distinguish the smaller group from the general population, as is the case in frail older individuals.^19,25 Second, age range data are presented; the studies were reviewed for the age range of participants to see if the upper end of the range crossed the 80-year age threshold (Table 1^1–18).

Chronic disease CPG assessment

Table 2^1–18 summarizes the findings from the review of the 14 CPGs included in this study. All CPGs specifically addressed individuals older than 65 years of age in their rationale and background sections. However, only the 2008 CPG for diabetes and the 2006 and 2007 CPGs for heart failure included specific sections on the prevention and management of these conditions in individuals older than 65 years of age.

Twelve CPGs provided specific recommendations for individuals older than 65 years of age. The 4 hypertension CPG updates,^6–13 however, all provided the same 3 recommendations, 2 of which cautioned the use of a recommended therapy (combination therapy and β-blockers) in elderly patients. Similarly, the only recommendation for older individuals in the 2002,¹⁴ 2006,¹⁵ and 2010¹⁶ osteoporosis CPGs identified individuals older than 65 years of age as being at risk of fragility fractures, suggesting that bone mineral density tests be conducted in this population. The 2008 stroke update¹⁸ provided 1 recommendation on sodium intake for individuals aged 50 to 70 years and 70 years or older. Neither the 2006 stroke CPG¹⁷ nor the 2008 heart failure CPG³ provided recommendations specific to the 65-years-and-older age group.

With regard to frail individuals or those older than 80 years of age, 5 CPGs provided specific recommendations. All heart failure guidelines, except the 2008 update, addressed the need for frail elderly heart failure patients to be treated as a unique population.^2,4,5 The 2009 hypertension^6,7 and 2008 stroke¹⁸ updates both recommended using caution in carrying out recommended therapies with frail elderly patients and acknowledged the lack of clinical trial data in this population.

Chronic disease CPGs and multiple chronic conditions

Most of the CPGs (13 of 14^{1–14,16–18}) discussed and provided specific recommendations for the treatment of their target conditions in the presence of at least 1 other condition, providing at least 1 specific recommendation on the issue of comorbidity. However, consideration of other comorbidities only occurred when a particular comorbidity formed part of a specific paradigm for an adverse outcome, such as when considering the management of hypertension in patients with diabetes. It was rare for guidelines to consider the effect of unrelated comorbidities, in particular multiple comorbidities or polypharmacy, on the disease management recommendations. The 2006 heart failure CPG⁵ was the only guideline to identify the high comorbid disease burden present in frail elderly patients.

Assessment of evidence in CPG development

Summaries of the mean ages and, where provided, SDs of the participants in the studies used as evidence in the 14 CPGs reviewed are presented in Figures 1 to 5* and Table 1.^1–18

Conclusion

Evidence-based chronic disease CPGs aim to provide standards to improve the quality of care for people with chronic diseases. However, there appears to be a substantial gap between the participant population in the many evidence-based trials that are used to create recommendations in CPGs and the diverse population to whom these CPGs might be generalized. Further investigation into the applicability of research findings and recommendations for populations in advanced old age needs to be conducted. A new approach that takes into account the possible interaction of multiple recommendations and multiple medications, as well as recognizing the mental and functional issues often present in the elderly population, should be considered.