PURPOSE: Periodic limb movement disorder (PLMD) is a common sleep disorder that has been described in several medical conditions including end stage renal disease, iron deficiency, sickle cell anemia, pregnancy, chronic lung disease, myelopathies and neuropathies. Sleep disturbances are common in cancer patients. The contribution of PLMD to sleep disturbances in cancer patients has not been established.
METHODS: We undertook a retrospective chart review of 1015 patients who underwent nocturnal polysomnography at the UT MD Anderson Cancer Center between October 2006 and February 2011. Results are as below and are expressed in percentages and as group means.
RESULTS: Of the 1015 patients, 43 (4.8%) had a diagnosis of RLS and 147 (16%) had a diagnosis of PLMD (PLM index of 5/hour of sleep by AASM scoring criteria). 71 patients were male and the mean age was 61 years(y) with 44% of PLMD patients above 65 y. The most common malignancies were breast cancer (24.5%), hematologic malignancies (16%), lung cancer (10.8%), prostate cancer (9.5%) and melanoma (4.7%). 30(20%) patients had known exposure to platinum based or taxane chemotherapeutic agents known to cause peripheral neuropathy. Mean ESS score was 10.9. Mean PLMD index and PLMD arousal index in these patients were 49 and 8.9 respectively. Diabetes mellites and renal disease were co-morbid in 39 (26.5%) and 8 (5.4%) patients respectively. The mean ferritin level was 203; 33% of the patients had a low ferritin value (< 50 ng/milliliter). 61 (41.4%) patients were on selective serotonin reuptake inhibitors. Mean sleep efficiency was 79 % and stage N3 was decreased at 2.6 % of total sleep time (median age of the study group was 62 y). Sleep disordered breathing was comorbid in 74.8% of the patients with a mean AHI of 25.
CONCLUSIONS: To our knowledge, this is the first time a study has been undertaken to describe PLMD in cancer patients.
CLINICAL IMPLICATIONS: Recognition of presence of PLMD and its causes may have significant implications in the understanding of sleep disturbances in cancer patients.
DISCLOSURE: The following authors have nothing to disclose: Reeba Mathew, Saadia Faiz, Brenda Remmert, Stephen Mahoney, Guadalupe Pacheco, Leendert Keus, Lara Bashoura, Diwakar Balachandran
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