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Latent Class Analysis to Classify Patients with Transthyretin Amyloidosis by Signs and Symptoms

View Article: PubMed Central

ABSTRACT

Introduction: The aim of this study was to develop an empirical approach to classifying patients with transthyretin amyloidosis (ATTR) based on clinical signs and symptoms.

Methods: Data from 971 symptomatic subjects enrolled in the Transthyretin Amyloidosis Outcomes Survey were analyzed using a latent class analysis approach. Differences in health status measures for the latent classes were examined.

Results: A four-class latent class solution was the best fit for the data. The latent classes were characterized by the predominant symptoms as severe neuropathy/severe autonomic, moderate to severe neuropathy/low to moderate autonomic involvement, severe cardiac, and moderate to severe neuropathy. Incorporating disease duration improved the model fit. It was found that measures of health status varied by latent class in interpretable patterns.

Conclusion: This latent class analysis approach offered promise in categorizing patients with ATTR across the spectrum of disease. The four-class latent class solution included disease duration and enabled better detection of heterogeneity within and across genotypes than previous approaches, which have tended to classify patients a priori into neuropathic, cardiac, and mixed groups. Although this study utilized a cross-sectional approach to disease duration, future work could include the application of longitudinal latent class analyses.

Funding: Pfizer Inc., New York, NY, USA.

Electronic supplementary material: The online version of this article (doi:10.1007/s40120-015-0028-y) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Item response probabilities by LC and disease duration (<4 and ≥4 years): a LC1, b LC2, c LC3, d LC4. LC latent class, LC1 severe neuropathy/severe autonomic, LC2 moderate to severe neuropathy/low to moderate autonomic involvement, LC3 severe cardiac, LC4 moderate to severe neuropathy
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Fig1: Item response probabilities by LC and disease duration (<4 and ≥4 years): a LC1, b LC2, c LC3, d LC4. LC latent class, LC1 severe neuropathy/severe autonomic, LC2 moderate to severe neuropathy/low to moderate autonomic involvement, LC3 severe cardiac, LC4 moderate to severe neuropathy

Mentions: Each patient had a probability calculated for membership in each of the four LCs and was assigned to the LC with the highest probability. The individual posterior probabilities used to categorize patients into LCs were strong, with means within LC ranging from 0.91 to 0.98 (Table 1). The estimated item response probabilities for each LC grouped by ATTR duration are shown in Fig. 1 and in Table S1 in the electronic supplementary material (ESM).Table 1


Latent Class Analysis to Classify Patients with Transthyretin Amyloidosis by Signs and Symptoms
Item response probabilities by LC and disease duration (<4 and ≥4 years): a LC1, b LC2, c LC3, d LC4. LC latent class, LC1 severe neuropathy/severe autonomic, LC2 moderate to severe neuropathy/low to moderate autonomic involvement, LC3 severe cardiac, LC4 moderate to severe neuropathy
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4470973&req=5

Fig1: Item response probabilities by LC and disease duration (<4 and ≥4 years): a LC1, b LC2, c LC3, d LC4. LC latent class, LC1 severe neuropathy/severe autonomic, LC2 moderate to severe neuropathy/low to moderate autonomic involvement, LC3 severe cardiac, LC4 moderate to severe neuropathy
Mentions: Each patient had a probability calculated for membership in each of the four LCs and was assigned to the LC with the highest probability. The individual posterior probabilities used to categorize patients into LCs were strong, with means within LC ranging from 0.91 to 0.98 (Table 1). The estimated item response probabilities for each LC grouped by ATTR duration are shown in Fig. 1 and in Table S1 in the electronic supplementary material (ESM).Table 1

View Article: PubMed Central

ABSTRACT

Introduction: The aim of this study was to develop an empirical approach to classifying patients with transthyretin amyloidosis (ATTR) based on clinical signs and symptoms.

Methods: Data from 971 symptomatic subjects enrolled in the Transthyretin Amyloidosis Outcomes Survey were analyzed using a latent class analysis approach. Differences in health status measures for the latent classes were examined.

Results: A four-class latent class solution was the best fit for the data. The latent classes were characterized by the predominant symptoms as severe neuropathy/severe autonomic, moderate to severe neuropathy/low to moderate autonomic involvement, severe cardiac, and moderate to severe neuropathy. Incorporating disease duration improved the model fit. It was found that measures of health status varied by latent class in interpretable patterns.

Conclusion: This latent class analysis approach offered promise in categorizing patients with ATTR across the spectrum of disease. The four-class latent class solution included disease duration and enabled better detection of heterogeneity within and across genotypes than previous approaches, which have tended to classify patients a priori into neuropathic, cardiac, and mixed groups. Although this study utilized a cross-sectional approach to disease duration, future work could include the application of longitudinal latent class analyses.

Funding: Pfizer Inc., New York, NY, USA.

Electronic supplementary material: The online version of this article (doi:10.1007/s40120-015-0028-y) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus