Loss to Follow-Up Among Patients With Proliferative Diabetic Retinopathy in Clinical Practice.

PURPOSE: To determine the proportion of patients with proliferative diabetic retinopathy (PDR) who were counted as loss to follow-up (LTFU) patients and to investigate predictive factors. DESIGN: Retrospective cohort study. METHODS: Information was collected for 4,423 patients with PDR between April 30, 2012, and April 30, 2017. Two definitions of LTFU were used. Complete LTFU referred to the population who never returned to care within the study period. Interval LTFU referred to the population who did not adhere to clinical recommendations and missed scheduled appointments, resulting in intervals longer than 6 months or 1 year between 2 appointments. Age, average gross income, and insurance were assessed as potential predictors of interval LTFU. RESULTS: Among 4,423 patients with PDR, 2,407 (54.4%) and 2,320 (52.4%) were complete LTFU at 6 months and 1 year, respectively; 782 (17.7%) and 468 (10.6%) patients were interval LTFU for 6 months and 1 year, respectively. Age and average gross income were not found to be significant predictors of interval LTFU. Compared to self-pay, government and private insurance patients were more likely to be interval LTFU at 6 months (government, P = .035; private, P = .005). Private insurance patients were also more likely to be interval LTFU at 1 year (P = .003). CONCLUSIONS: The identified complete LTFU rates were notably high and warrant further study. More than 1 of 6 patients were interval LTFU for at least 6 months, and 1 of 10 patients was interval LTFU for more than 1 year. Insurance status was significant in determining interval LTFU status. Consistent with other analyses, these results indicate that compliance with clinical appointments among patients with PDR is a substantial clinical challenge.

Assessment of Femoral Head Revascularization in Legg-Calvé-Perthes Disease Using Serial Perfusion MRI.

BACKGROUND: Legg-Calvé-Perthes disease is a juvenile form of osteonecrosis of the femoral head. The purpose of this study was to use serial perfusion magnetic resonance imaging (MRI) to determine the pattern and rate of revascularization of the femoral heads of patients with the active stage of Legg-Calvé-Perthes disease. METHODS: We performed a prospective study of 29 patients (30 hips) with a mean age (and standard deviation) of 8.4 ± 1.9 years who were diagnosed with Waldenström Stage-1 or 2 Legg-Calvé-Perthes disease. All patients had ≥2 perfusion MRIs, and 21 patients (22 hips) had ≥3. Perfusion percentages of the femoral epiphyses were measured by 2 independent observers. Statistical analyses included calculation of the intraclass correlation coefficient, the paired t test, the Mann-Whitney U test, and the Kruskal-Wallis test. RESULTS: Initial perfusion MRIs showed the percent perfusion in the affected femoral heads to range from 5% to 70%. The average percent perfusion (and standard deviation) was 35% ± 16% on the first MRI, which increased to 77% ± 14% on the follow-up MRI acquired at an average of 10.5 ± 2.9 months later (p < 0.01). Serial assessment showed a general pattern of revascularization starting from the periphery of the posterior, lateral, and medial aspects of the femoral epiphysis and converging toward the anterocentral region. The average rate of revascularization was 4.9% ± 2.3% per month with a wide range among the patients (0.6% to 10.4% per month). CONCLUSIONS: Revascularization of the necrotic femoral head increased over time in a horseshoe pattern, starting from the posterior, lateral, and medial aspects of the femoral epiphysis. The rate of revascularization was highly variable among patients. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Legg-Calvé-Perthes disease produces chronic hip synovitis and elevation of interleukin-6 in the synovial fluid.

Legg-Calvé-Perthes disease (LCPD) is a childhood hip disorder of ischemic osteonecrosis of the femoral head. Hip joint synovitis is a common feature of LCPD, but the nature and pathophysiology of the synovitis remain unknown. The purpose of this study was to determine the chronicity of the synovitis and the inflammatory cytokines present in the synovial fluid at an active stage of LCPD. Serial MRI was performed on 28 patients. T2-weighted and gadolinium-enhanced MR images were used to assess synovial effusion and synovial enhancement (hyperemia) over time. A multiple-cytokine assay was used to determine the levels of 27 inflammatory cytokines and related factors present in the synovial fluid from 13 patients. MRI analysis showed fold increases of 5.0 ± 3.3 and 3.1 ± 2.1 in the synovial fluid volume in the affected hip compared to the unaffected hip at the initial and the last follow-up MRI, respectively. The mean duration between the initial and the last MRI was 17.7 ± 8.3 months. The volume of enhanced synovium on the contrast MRI was increased 16.5 ± 8.5 fold and 6.3 ± 5.6 fold in the affected hip compared to the unaffected hip at the initial MRI and the last follow-up MRI, respectively. In the synovial fluid of the affected hips, IL-6 protein levels were significantly increased (LCPD: 509 ± 519 pg/mL, non-LCPD: 19 ± 22 pg/mL; p = 0.0005) on the multi-cytokine assay. Interestingly, IL-1ß and TNF-α levels were not elevated. In the active stage of LCPD, chronic hip synovitis and significant elevation of IL-6 are produced in the synovial fluid. Further studies are warranted to investigate the role of IL-6 on the pathophysiology of synovitis in LCPD and how it affects bone healing.