https://orcid.org/0000-0002-4426-4644
Dear Editor,
Wang et al.Citation1 determined rates of hospitalization and in-hospital mortality in the first year in patients with cardiac amyloidosis (CA). According to three datasets, incidence rates of hospitalization were 78.4, 78.6 and 61.2 per 100 person-years. In addition, rates of in-hospital mortality were 16.5, 8.4 and 17.7 per 100 person-years. Furthermore, the prognosis improved when comparing the period between 2004–2011 and 2010–2017. The authors emphasized the need to explore the risk factors associated with poor prognoses by considering the type of CA. I discuss a recent report regarding to their comment.
Barge-Caballero et al.Citation2 evaluated the prognosis of CA with special reference to light-chain amyloidosis (AL-CA) and transthyretin amyloidosis (ATTR-CA). Data collection was made between 1998 and 2018. One-year, 3-year, and 5-year survival rates in AC-AL patients were 43.3%, 40.4% and 35.4%, and those in ATTR-CA patients were 85.1%, 57.3% and 31.4%, respectively. Adjusted hazard ratios (95% CIs) of AL-CA subtype, previous admission for heart failure, class III–IV of a New York Heart Association functional classification and beta-blocker therapy for mortality were 3.41 (1.45–8.06), 4.25 (1.63–11.09), 2.76 (1.09–7.03) and 0.23 (0.09–0.59), respectively. Although they mentioned that AL-CA presented a poor prognosis, survival rate sharply decreased in ATTR-CA patients after one year, which might reflect poor long-term prognosis. The crossing hazards of survival curve between the AC-AL group and the ATTR-CA group reflects inappropriate application for Cox regression model. In order to detect differences in survival curve in the lack of proportionality of hazards, there is a need to choose an alternative method instead of the standard log-rank test and Cox regression analysisCitation3–5.
Further studies are needed to specify the prognosis in patients with CA.
Transparency
Declaration of funding
None received.
Declaration of financial/other relationships
The author of this manuscript has no relevant financial or other relationships to disclose.
Acknowledgements
None.
References
- Wang L, Swerdel JN, Weaver J, et al. Incidence rate of hospitalization and mortality in the first year following initial diagnosis of cardiac amyloidosis in the US claims databases. Curr Med Res Opin. 2021;37(8):1275–1281.
- Barge-Caballero G, Vázquez-García R, Barge-Caballero E, et al. Light chain and transthyretin cardiac amyloidosis: clinical characteristics, natural history and prognostic factors. Med Clin (Barc). 2021;156(8):369–378.
- Liu T, Ditzhaus M, Xu J. A resampling-based test for two crossing survival curves. Pharm Stat. 2020;19(4):399–409.
- Kuitunen I, Ponkilainen VT, Uimonen MM, et al. Testing the proportional hazards assumption in Cox regression and dealing with possible non-proportionality in total joint arthroplasty research: methodological perspectives and review. BMC Musculoskelet Disord. 2021;22(1):489.
- Dormuth I, Liu T, Xu J, et al. Which test for crossing survival curves? A user’s guideline. BMC Med Res Methodol. 2022;22(1):34.