Patients reporting moderate or extreme pain a year after a myocardial infarction (MI) — even pain due to other health conditions — are more likely to die within the next 8 years than those without post-MI pain, new research suggests.
In the analysis of post-MI health data for more than 18,300 Swedish adults, those with moderate pain were 35% more likely to die from any cause during follow-up compared with those with no pain, and those with extreme pain were more than twice as likely to die.
Furthermore, pain was a stronger predictor of mortality than smoking.
“For a long time, pain has been regarded as merely a symptom of disease rather than a disease” in its own right, Linda Vixner, PT, PhD, of Dalarna University in Falun, Sweden told theheart.org | Medscape Cardiology.
Updated definitions of chronic pain in the ICD-11, as well as a recent study using data from the UK Biobank showing that chronic pain is associated with an increased risk of cardiovascular disease, prompted the current study, which looks at the effect of pain on long-term survival after an MI.
“We did not expect that pain would have such a strong impact on the risk of death, and it also surprised us that the risk was more pronounced than that of smoking,” Vixner said. “Clinicians should consider pain an important cardiovascular risk factor.”
The study was published online August 16 in the Journal of the American Heart Association.
“Experienced Pain“ Prognostic
The investigators analyzed data from the SWEDEHEART registry of 18,376 patients who had an MI in 2004-2013. The mean age of patients was 62 years and 75% were men. Follow-up time was 8.5 years (median, 3.37).
Self-reported levels of experienced pain according to the EuroQol five-dimension instrument were recorded 12 months after hospital discharge.
Moderate pain was reported by 38.2% of patients and extreme pain by 4.5%.
In the extreme pain category, women were overrepresented (7.5% vs 3.6% of men), as were current smokers, and patients with diabetes, previous MI, previous stroke, previous percutaneous coronary intervention, non-ST-segment–elevation MI, and any kind of chest pain. Patients classified as physically inactive also were overrepresented in this category.
In addition, those with extreme pain had a higher body mass index and waist circumference 12 months after hospital discharge.
Most (73%) of the 7889 patients who reported no pain at the 2-month follow-up after MI were also pain-free at the 12-month follow-up, and 65% of those experiencing pain at 2 months were also experiencing pain at 12 months.
There were 1067 deaths. The adjusted hazard ratio was 1.35 for moderate pain and 2.06 for extreme pain.
As noted, pain was a stronger mortality predictor than smoking: C-statistics for pain were 0.60 and for smoking, 0.55.
“Clinicians managing patients after MI should recognize the need to consider experienced pain as a prognostic factor comparable to persistent smoking and to address this when designing individually adjusted [cardiac rehabilitation] and secondary prevention treatments,” the authors write.
Pain should be assessed at follow-up after MI, they add, and, as Vixner suggested, it should be “acknowledged as an important risk factor.”
“These findings parallel prior studies and my own clinical experience,” American Heart Association volunteer expert Gregg C. Fonarow, MD, interim chief of the Division of Cardiology at UCLA and director, Ahmanson-UCLA Cardiomyopathy Center, told theheart.org | Medscape Cardiology.
“There are many potential causes for patient-reported pain in the year after a heart attack,” he said, including a greater cardiovascular risk burden, more comorbid conditions, less physical activity, and chronic use of nonsteroidal anti-inflammatory medications or opioids for pain control — all of which can contribute to the increased risk of mortality.
Factors beyond those evaluated and adjusted for in the observational study may contribute to the observed associations, he added. “Socioeconomic factors were not accounted for [and] there was no information on the types, doses, and frequency of pain medication use.”
“Clinicians managing patients with prior MI should carefully assess experienced pain and utilize this information to optimize risk factor control recommendations, inform treatment decisions, and consider in terms of prognosis,” he advised.
Further studies should evaluate whether the associations hold true for other patient populations, Fonarow said. “In addition, intervention trials could evaluate if enhanced management strategies in these higher-risk patients with self-reported pain can successfully lower the mortality risk.”
Vixner sees a role for physical activity in lowering the mortality risk.
“One of the core treatments for chronic pain is physical activity,” she said. “It positively influences quality of life, activities of daily living, pain intensity, and overall physical function, and reduces the risk of social isolation” and cardiovascular diseases.
Her team recently developed the “eVISualisation of physical activity and pain” (eVIS) intervention, which aims to promote healthy physical activity levels in persons living with chronic pain. The intervention is currently being evaluated in an ongoing registry-based, randomized controlled trial.
The study was supported by Svenska Försäkringsföreningen, Dalarna University, Region Dalarna. Vixner and coauthors have reported no relevant financial relationships. Fonarow has disclosed consulting for Abbott, Amgen, AstraZeneca, Bayer, Cytokinetics, Eli Lilly, Johnson & Johnson, Medtronic, Merck, Novartis, and Pfizer.
J Am Heart Assoc. Published online August 16, 2023. Full text
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