DIAL: Randomized Trial of Telephonic Intervention in Chronic Heart Failure

Luis Gruberg, MD, FACC

Disclosures

November 21, 2002

Presenter: Daniel R. Nul, MD, Buenos Aires, Argentina

It is estimated that about 1% of the Argentinian population, amounting to almost 300,000 patients, suffer from heart failure of varying etiologies.[1] Over one-third of these patients are hospitalized every year, and annual mortality rates are reported to be as high as 10% to 20%. These statistics are not exclusive to Argentina; the high incidence and prevalence rates of heart failure also continue to plague other countries, particularly the United States. Unfortunately, treatment compliance among heart failure patients can be poor, and this is known to adversely impact clinical outcomes. In addition, caring for these large numbers of patients can become exceedingly difficult, particularly in areas with limited access to hospitals and transportation. Closer monitoring of heart failure patients may help ensure that prescribed therapies are maintained and clinical outcomes improved.

Methods

The premise behind the RanDomized Trial of Telephonic Intervention in Chronic HeArt FaiLure (DIAL) study was very simple: to see whether a program based on centralized telephone intervention performed by trained nurses can reduce the high rates of morbidity and mortality associated with chronic heart failure compared with "usual care" administered by an attending cardiologist.

Content and Frequency of Phone Calls

The nurses who operated the single surveillance telephone intervention program were trained to provide education, counseling, and monitoring support to patients with varying degrees of chronic heart failure. As part of the trial, during each phone call, nurses would query patients about fatigue or episodes of dyspnea, drug therapy (especially compliance), daily weight control, edema, diet, and physical activity (Table 1). The content and frequency of the calls were tailored according to the severity of the patient's status. The first 4 calls were placed every 14 days. Thereafter, patients with NYHA Class IV heart failure were called more frequently (every 7 days) than NYHA Class III patients (every 14 days) and NYHA Class I/II patients (every 30 days). The nurses were also given the discretion to change the frequency of the calls or adjust diuretic dosages based on their evaluation of the patient.

Table 1. DIAL: Definitions of Educating, Counseling, and Monitoring
Variable Measures
Dyspnea/fatigue Activity scale for each call
Acknowledgment of dyspnea progression
Drug therapy Compliance strategies

Flexible diuretics regimen

Weight control Weight changes
Edema Onset or progression of edema
Diet Sodium and fluid restriction

Selection and preparation of food

Physical activity Working and leisure activities

Walking incentives


According to investigators, the phone system utilized for this particular study was more advanced than in previous studies. The system used a computer program that analyzed the data recorded by nurses to generate daily call lists, which prevented patients from becoming lost in the system.

Enrollment Criteria

As part of the Heart Failure Study Group in Argentina (Grupo de Estudio de la Sobrevida de la Insuficiencia Cardiaca en Argentina [GESICA]), the DIAL trial randomized a total of 1518 patients from 51 medical centers in Argentina to either telephone intervention (n = 760) or usual care (n = 758) (Figure 1). Patients were followed for an average of 457 days. Candidates for trial participation had to be diagnosed with chronic heart failure ≥ 3 months prior to enrollment and must have remained stable for the 2 previous months on optimal medical therapy. Patients were excluded if phone accessibility was limited or if they had required more than 1 medical visit within the last month. Additional exclusion criteria included: restrictive or hypertrophic cardiomyopathy, significant valvular disease, significant pericardial disease, primary pulmonary hypertension, congenital heart disease, acute coronary syndrome (within the previous 3 months), or any disease with a reduced survival expectancy.

The primary composite endpoint of the trial was all-cause mortality and/or heart failure hospital admissions. Secondary endpoints included all-cause mortality, cardiovascular mortality, all-cause hospitalizations, admissions for worsening heart failure, quality of life, and cost-effectiveness.

Figure 1. DIAL: study design.
Results

The baseline clinical characteristics (Table 2) and baseline medical management (Table 3) for the 2 groups were well balanced.

Table 2. DIAL: Baseline Clinical Characteristics
  Telephone Intervention
(n = 760)
Control
(n = 758)
Age (yrs) 65 65
Female (%) 27 30
Diabetes (%) 20 21
Hypertension (%) 60 59
Heart failure admissions (%) 35 39
NYHA Class III/IV (%) 49 48
Systolic dysfunction (%) 78 81
S/P MI/Angina (%) 45 43
Table 3. DIAL: Baseline Medical Management
  Telephone Intervention
(n = 760)
Control
(n = 758)
Diuretics (%) 82 84
Digoxin (%) 45 49
Amiodarone (%) 29 29
ACE inhibitors (%) 78 81
Spironolactone (%) 32 33
Beta-blockers (%) 61 62


Investigators reported that there was a statistically significant 20% reduction in the primary endpoint (death/heart failure admissions) in patients randomized to telephone intervention (P = .026; Figure 2). There was also a 29% reduction in admissions due to worsening heart failure (P = .005; Figure 3). However, there was no significant difference in total mortality rates between the 2 groups (Figure 4).

Figure 2. DIAL: primary endpoint: all-cause mortality/heart failure hospitalizations.
Figure 3. DIAL: heart failure hospitalization.
Figure 4. DIAL: all-cause mortality.

The intervention group also had lower rates of all-cause (P = .05; Figure 5) and cardiovascular (P = .006; Figure 6) hospital admissions. According to Dr. Nul, 1 heart failure hospitalization can be prevented for every 18 patients who participate in telephone intervention programs.

Figure 5. DIAL: all-cause hospitalization.
Figure 6. DIAL: cardiovascular hospitalization.
Conclusion

The results of the DIAL trial indicate that a centralized telephone intervention program is effective in reducing the endpoint of morbidity and/or mortality in patients with chronic heart failure. The primary endpoint was influenced most by the significant improvement in limiting the number of hospital admissions due to worsening heart failure. The results of DIAL indicate that communicating with the patient on a regular basis will help identify symptoms and conditions that may facilitate an office visit and thus preempt the need for hospitalization.

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