Physical HF symptoms were measured using the HFSPS, V.3, an 18-item Likert scale. The original scale22 (link) was expanded from 12 items to 18 to capture the more subtle symptoms of HF. Importantly, the development of the original HFSPS and this current 18 item version were guided by Lenz’s Theory of Unpleasant Symptoms, with respect to interactions among multiple symptoms, multiple influential pathophysiological mechanisms, situational factors, and performance (e.g. HRQOL and clinical event-risk).23 (link),24 (link) Additional items were added to assess dyspnea on exertion, fatigue, nocturia, and symptoms associated with right-sided congestion (i.e. abdominal swelling and loss of appetite).25 (link) The HFSPS asks participants how much they are bothered by symptoms in the past week using 5 response options ranging from 0 (I did not have the symptom) to 5 (extremely bothersome). Scores are summed with higher values indicating higher symptom burden.
Convergent validity provides evidence of validity by examining the correlation between different measures of a construct. To support convergent validity, correlation of theoretically-related construct measures should be high.26 ,27 (link) The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a 23-item Likert scale health status measure that assesses physical function, symptoms, social function, self-efficacy, and quality of life among patients with HF.28 (link) The KCCQ is a reliable and valid measure of health status responsive to change clinical status. The 6-item Physical Limitation subscale of the (KCCQ) was used to examine convergent validity. Scores range 1 to 36 on the Physical Limitation subscale. Higher scores indicate better function. The reliability of the Physical Limitation subscale is acceptable with a Cronbach’s alpha of 0.90. We hypothesized that the correlation between the HFSPS and KCCQ Physical Limitation subscale would be significant.
Discriminant validity examines differentiation of constructs that are theoretically different. To support discriminant validity, correlation between two different constructs should be low.26 ,27 (link) The Self-Care of HF Index (SCHFI) was used to quantify self-care.29 (link) The SCHFI v.6.2 is a 22-item scale using a 4-point self-report response format to measure self-care maintenance (adherence behaviors), self-care management (response to symptoms) and self-care confidence. The 6-item Self-Care Management score was used to examine discriminant validity for this analysis because it reflects how quickly participants recognized and responded symptoms as opposed to the physical experience of symptoms. Symptom recognition options ranged from 0 (I did not recognize it as a symptom of HF) to 4 (very quickly). Response to symptoms options included rating the likelihood of taking action to manage symptoms (e.g. taking an extra diuretic, reducing fluid intake) from 1 (not likely) to 4 (very likely). Scores are standardized to range from 0 to 100 with higher values indicated better symptom response behaviors. The Self-Care Management subscale of the SCHFI is multidimensional with a two factor structure representing symptom evaluation and treatment implementation. Therefore, a global reliability index is used to assess internal consistency. The global reliability index derived from the weighted least squares means and variance is 0.77 and 0.76 respectively.30 (link) We hypothesized that the correlation between the HFSPS and SCHFI Self-Care Management subscale would be weak and insignificant.
We completed a review of the electronic medical record at 1 year looking specifically for HF-related emergency room visits, hospitalizations or mortality. For the vast majority of events data were extracted directly from discharge summaries all participants received care locally and were part of an extensively-linked electronic medical record system. We also contacted study participants by phone to inquire about events that occurred outside of the health system network; we solicited sufficient detail directly from participants or their family members to determine whether or not the event was primarily related to their HF or for other reasons. All events underwent adjudication by two separate evaluators until 100% agreement was reached about the underlying reasons for emergent healthcare utilization.
Convergent validity provides evidence of validity by examining the correlation between different measures of a construct. To support convergent validity, correlation of theoretically-related construct measures should be high.26 ,27 (link) The Kansas City Cardiomyopathy Questionnaire (KCCQ) is a 23-item Likert scale health status measure that assesses physical function, symptoms, social function, self-efficacy, and quality of life among patients with HF.28 (link) The KCCQ is a reliable and valid measure of health status responsive to change clinical status. The 6-item Physical Limitation subscale of the (KCCQ) was used to examine convergent validity. Scores range 1 to 36 on the Physical Limitation subscale. Higher scores indicate better function. The reliability of the Physical Limitation subscale is acceptable with a Cronbach’s alpha of 0.90. We hypothesized that the correlation between the HFSPS and KCCQ Physical Limitation subscale would be significant.
Discriminant validity examines differentiation of constructs that are theoretically different. To support discriminant validity, correlation between two different constructs should be low.26 ,27 (link) The Self-Care of HF Index (SCHFI) was used to quantify self-care.29 (link) The SCHFI v.6.2 is a 22-item scale using a 4-point self-report response format to measure self-care maintenance (adherence behaviors), self-care management (response to symptoms) and self-care confidence. The 6-item Self-Care Management score was used to examine discriminant validity for this analysis because it reflects how quickly participants recognized and responded symptoms as opposed to the physical experience of symptoms. Symptom recognition options ranged from 0 (I did not recognize it as a symptom of HF) to 4 (very quickly). Response to symptoms options included rating the likelihood of taking action to manage symptoms (e.g. taking an extra diuretic, reducing fluid intake) from 1 (not likely) to 4 (very likely). Scores are standardized to range from 0 to 100 with higher values indicated better symptom response behaviors. The Self-Care Management subscale of the SCHFI is multidimensional with a two factor structure representing symptom evaluation and treatment implementation. Therefore, a global reliability index is used to assess internal consistency. The global reliability index derived from the weighted least squares means and variance is 0.77 and 0.76 respectively.30 (link) We hypothesized that the correlation between the HFSPS and SCHFI Self-Care Management subscale would be weak and insignificant.
We completed a review of the electronic medical record at 1 year looking specifically for HF-related emergency room visits, hospitalizations or mortality. For the vast majority of events data were extracted directly from discharge summaries all participants received care locally and were part of an extensively-linked electronic medical record system. We also contacted study participants by phone to inquire about events that occurred outside of the health system network; we solicited sufficient detail directly from participants or their family members to determine whether or not the event was primarily related to their HF or for other reasons. All events underwent adjudication by two separate evaluators until 100% agreement was reached about the underlying reasons for emergent healthcare utilization.