Muchtar, Eli

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SummaryThe significance of serum lactate dehydrogenase (LDH) in light chain (AL) amyloidosis has not been previously explored. We studied 1019 newly diagnosed patients and correlated the elevation of LDH above the upper limit of normal (ULN) with disease characteristics and outcome. Four hundred and nine patients had an LDH above ULN, representing 40% of the study population. Patients with an elevated LDH were older, were less likely to be male and had more extensive organ involvement compared to patients with a normal LDH. Patients with high LDH had greater cardiac and renal dysfunction. Elevated LDH was an independent prognostic marker for overall survival and for death within 6 months of diagnosis, but this was restricted to patients not eligible for stem cell transplant. Serum LDH may act as a marker for organ damage and should be explored as a potential marker for tissue healing and organ recovery.

AbstractBackgroundData on the effect of systemic immunoglobulin light chain amyloidosis (AL amyloidosis) on thyroid function are limited.ObjectiveTo assess the prevalence of hypothyroidism in AL amyloidosis patients and determine its predictors.Methods1142 newly diagnosed AL amyloidosis patients were grouped based on the thyroid‐stimulating hormone (TSH) measurement at diagnosis: hypothyroid group (TSH above upper normal reference; >5 mIU L−1; n = 217, 19% of study participants) and euthyroid group (n = 925, 81%). Predictors for hypothyroidism were assessed in a binary multivariate model. Survival between groups was compared using the log‐rank test and a multivariate analysis.ResultsPatients with hypothyroidism were older, more likely to present with renal and hepatic involvement and had a higher light chain burden compared to patients in the euthyroid group. Higher proteinuria in patients with renal involvement and lower albumin in patients with hepatic involvement were associated with hypothyroidism. In a binary logistic regression model, age ≥65 years, female sex, renal involvement, hepatic involvement, kappa light chain restriction and amiodarone use were independently associated with hypothyroidism. Ninety‐three per cent of patients in the hypothyroid group with free thyroxine measurement had normal values, consistent with subclinical hypothyroidism. Patients in the hypothyroid group had a shorter survival compared to patients in the euthyroid group (4‐year survival 36% vs 43%; P = 0.008), a difference that was maintained in a multivariate analysis.ConclusionA significant proportion of patients with AL amyloidosis present with hypothyroidism, predominantly subclinical, which carries a survival disadvantage. Routine assessment of TSH in these patients is warranted.

Key Points Significant improvement in outcome is a reality for newly diagnosed AL amyloidosis in the past decade. Six-month mortality among transplant ineligible patients has declined since 2005.