Safety and efficacy of long-term nicotinamide mononucleotide supplementation on metabolism, sleep, and nicotinamide adenine dinucleotide biosynthesis in healthy, middle-aged Japanese men.

Obesity and aging are major risk factors for several life-threatening diseases. Accumulating evidence from both rodents and humans suggests that the levels of nicotinamide adenine dinucleotide (NAD+), a regulator of many biological processes, declines in multiple organs and tissues with aging and obesity. Administration of an NAD+ intermediate, nicotinamide mononucleotide (NMN), replenishes intracellular NAD+ levels and mitigates aging- and obesity-associated derangements in animal models. In this human clinical study, we aimed to investigate the safety and effects of 8-week oral administration of NMN on biochemical, metabolic, ophthalmologic, and sleep quality parameters as well as on chronological alterations in NAD+ content in peripheral tissues. An 8-week, single-center, single-arm, open-label clinical trial was conducted. Eleven healthy, middle-aged Japanese men received two 125-mg NMN capsules once daily before breakfast. The 8-week NMN supplementation regimen was well-tolerated; NAD+ levels in peripheral blood mononuclear cells increased over the course of NMN administration. In participants with insulin oversecretion after oral glucose loading, NMN modestly attenuated postprandial hyperinsulinemia, a risk factor for coronary artery disease (n = 3). In conclusion, NMN overall safely and effectively boosted NAD+ biosynthesis in healthy, middle-aged Japanese men, showing its potential for alleviating postprandial hyperinsulinemia.

Morphological alterations in corneal nerves of patients with dry eye and associated biomarkers.

The purposes of the present study were to (1) identify the relationship between dry eye symptoms and morphological changes in corneal subbasal nerves/ocular surfaces, and (2) discover tear film biomarkers indicating morphological changes in the subbasal nerves. This was a prospective cross-sectional study conducted between October and November 2017. Adults with dry eye disease (DED, n = 43) and healthy eyes (n = 16) were evaluated based on their subjective symptoms and ophthalmological findings. Corneal subbasal nerves were observed using confocal laser scanning microscopy. Nerve lengths, densities, branch numbers, and nerve fiber tortuosity were analyzed using ACCMetrics and CCMetrics image analysis systems; tear proteins were quantified by mass spectroscopy. Compared with the control group, the DED group had significantly lower tear breakup times (TBUT) and pain tolerance capacity, and significantly higher corneal nerve branch density (CNBD) and corneal nerve total branch density (CTBD). CNBD and CTBD showed significant negative correlations with TBUT. Six biomarkers (cystatin-S, immunoglobulin kappa constant, neutrophil gelatinase-associated lipocalin, profilin-1, protein S100-A8, and protein S100-A9) showed significant positive correlations with CNBD and CTBD. The significantly higher CNBD and CTBD in the DED group suggests that DED is associated with morphological alterations in corneal nerves. The correlation of TBUT with CNBD and CTBD further supports this inference. Six candidate biomarkers that correlate with morphological changes were identified. Thus, morphological changes in corneal nerves are a hallmark of DED, and confocal microscopy may help in the diagnosis and treatment of dry eyes.

Eosinophils promote corneal wound healing via the 12/15-lipoxygenase pathway.

Lipid mediators play important roles in regulating inflammatory responses and tissue homeostasis. Since 12/15-lipoxygenase (12/15-LOX)-derived lipid mediators such as lipoxin A4 (LXA4 ) and protectin D1 (PD1) protect against corneal epithelial cell damage, the major cell types that express 12/15-LOX and contribute to the corneal wound healing process are of particular interest. Here, we found that eosinophils were the major cell type expressing 12/15-LOX during the corneal wound healing process. Eosinophils were recruited into the conjunctiva after corneal epithelium wounding, and eosinophil-deficient and/or eosinophil-specific 12/15-LOX knockout mice showed delayed corneal wound healing compared with wild-type mice. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based mediator lipidomics revealed that a series of 12/15-LOX-derived mediators were significantly decreased in eosinophil-deficient mice and topical application of 17-hydroxydocosahexaenoic acid (17-HDoHE), a major 12/15-LOX-derived product, restored the phenotype. These results indicate that 12/15-LOX-expressing eosinophils, by locally producing pro-resolving mediators, significantly contribute to the corneal wound healing process in the eye.

Two case reports of continued progression of chronic ocular graft-versus-host disease without concurrent systemic comorbidities treated by amniotic membrane transplantation.

BACKGROUND: Chronic ocular graft-versus-host disease (oGVHD) is an ocular comorbidity of graft-versus-host disease (GVHD) that usually occurs concurrently with systemic manifestations. Failure to detect and treat oGVHD in its early stages may lead to progression of ocular signs and symptoms leading to oGVHD that is refractory to conventional treatment. CASE PRESENTATION: We report the clinical course of a 19-year-old male and a 59-year-old female with severe and progressive chronic oGVHD without concurrent systemic signs of chronic graft-versus-host disease (cGVHD). Although their systemic conditions had been stable, both suffered from severe oGVHD and were referred to our clinic. Both cases exhibited marked improvement in conjunctival inflammation and fibrotic changes after amniotic membrane transplantation (AMT). Both cases underwent keratoplasty eventually to stabilize ocular surface conditions and to improve visual function. CONCLUSIONS: We reported the clinical outcomes of 2 cases of chronic oGVHD without concurrent systemic comorbidities that were treated with AMT. The clinician should be aware that cGVHD may persist in target organs even in the absence of concurrent systemic comorbidities following seemingly successful systemic treatment. A multidisciplinary team approach is essential in the early detection and therapeutic intervention for chronic oGVHD.

Demodex-Mite Infestation in Cilia and its Association With Ocular Surface Parameters in Japanese Volunteers.

OBJECTIVES: To investigate the presence of Demodex mites on the eyelashes of a Japanese population and to explore its associations with subjective ocular symptoms and clinical ocular surface signs, including lid margin findings and fluorescein breakup time (FBUT). METHODS: Sixty-three Japanese Tokyo-based volunteers were examined (24 men and 39 women; mean±SD of age, 50.6±15.8 years). Eyelash sampling was performed by epilating three lashes from the center of the right upper eyelid. Eyelashes were tested for Demodex mites with a light microscope. The subjects completed questionnaires to assess subjective symptoms and risk factors for dry eye disease (DED) and underwent general examinations for DED, including FBUT and cornea-conjunctival staining with fluorescein. Meibomian gland function was also investigated in lid margin findings, vascularity and mucocutaneous junction movement, lid irregularity, plugging, pouting, and meibum secretion grade scores. RESULTS: Demodex mites were found in 20.6% (13/63) of the volunteers. Lid margin vascularity and meibum grades in the upper eyelid margins were significantly associated with the presence of Demodex mites. However, there were no significant differences in the diagnosis of meibomian gland dysfunction, FBUT, or ocular surface discomfort between the subjects with or without Demodex mites. CONCLUSIONS: Demodex mites are not rare in the cilia of a Japanese population. Lid margin vascularity and lower meibum quality may be associated with the presence of Demodex mites.

Galectin-3 is an amplifier of the interleukin-1ß-mediated inflammatory response in corneal keratinocytes.

Interleukin-1ß (IL-1ß) is a potent mediator of innate immunity commonly up-regulated in a broad spectrum of inflammatory diseases. When bound to its cell surface receptor, IL-1ß initiates a signalling cascade that cooperatively induces the expression of canonical IL-1 target genes such as IL-8 and IL-6. Here, we present galectin-3 as a novel regulator of IL-1ß responses in corneal keratinocytes. Using the SNAP-tag system and digitonin semi-permeabilization, we show that recombinant exogenous galectin-3 binds to the plasma membrane of keratinocytes and is internalized into cytoplasmic compartments. We find that exogenous galectin-3, but not a dominant negative inhibitor of galectin-3 polymerization lacking the N-terminal domain, exacerbates the response to IL-1ß by stimulating the secretion of inflammatory cytokines. The activity of galectin-3 could be reduced by a novel d-galactopyranoside derivative targeting the conserved galactoside-binding site of galectins and did not involve interaction with IL-1 receptor 1 or the induction of endogenous IL-1ß. Consistent with these observations, we demonstrate that small interfering RNA-mediated suppression of endogenous galectin-3 expression is sufficient to impair the IL-1ß-induced secretion of IL-8 and IL-6 in a p38 mitogen-activated protein kinase-independent manner. Collectively, our findings provide a novel role for galectin-3 as an amplifier of IL-1ß responses during epithelial inflammation through an as yet unidentified mechanism.

Accelerated Epithelial Proliferation in a Rabbit Model of Bullous Keratopathy.

Purpose: Long standing bullous keratopathy (BK) is associated with peripheral conjunctivalization and limbal deficiency. We hypothesized that cases of limbal deficiency may be induced due to accelerated proliferation of corneal epithelial cells. To investigate this hypothesis, we examined the influence of BK on the corneal epithelium in a rabbit model. Methods: Continuous curvilinear descemetorhexis was performed to remove a circular section of the corneal endothelium and Descemet's membrane (DM) using inverted Shinskey hook. Corneal tissue sections of BK eyes were observed by histochemical analysis using BrdU pulse chase methods for evaluation of corneal epithelial cell proliferation. Results: Rabbit corneas immediately became stromal edematous after DM stripping surgery, and a week later their thickness was five times that of control cornea. Vascularization of the peripheral cornea was observed in BK eyes, however, conjunctivalization was rarely observed at 6 weeks. The number of BrdU positive cells tended to be lower in the BK cornea epithelium compared to the control cornea epithelium. The number of Ki67 positive cells also showed a tendency to increase in the BK corneal epithelium. Telomere intensity in BK was similar to control corneal epithelium. Conclusion: BK may accelerate the proliferation of corneal epithelial cells in a rabbit model.

Differential effect of rebamipide on transmembrane mucin biosynthesis in stratified ocular surface epithelial cells.

Mucins are a group of highly glycosylated glycoproteins responsible for the protection of wet-surfaced epithelia. Recent data indicate that transmembrane mucins differ in their contribution to the protective function of the ocular surface, with MUC16 being the most effective barrier on the apical surface glycocalyx. Here, we investigated the role of the mucoprotective drug rebamipide in the regulation of transmembrane mucin biosynthesis using stratified cultures of human corneal and conjunctival epithelial cells. We find that the addition of rebamipide to corneal, but not conjunctival, epithelial cells increased MUC16 protein biosynthesis. Rebamipide did not affect the levels of MUC1, 4 and 20 compared to control. In these experiments, rebamipide had no effect on the expression levels of Notch intracellular domains, suggesting that the rebamipide-induced increase in MUC16 biosynthesis in differentiated corneal cultures is not regulated by Notch signaling. Overall these findings indicate that rebamipide induces the differential upregulation of MUC16 in stratified cultures of human corneal epithelial cells, which may have implications to the proper restoration of barrier function in ocular surface disease.

The impact of tear functions on visual outcome following keratoplasty in eyes with keratoconus.

BACKGROUND: To investigate the impact of preoperative and postoperative tear functions on visual outcome and the recovery of visual function following keratoplasty in eyes with keratoconus. METHODS: Twenty-five eyes of 25 consecutive patients (5 females, 20 males, mean age: 34.3 ± 15.8 years (range: 19-70 years) with keratoconus who underwent either penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK) were included in this prospective study. One patient who had a rejection episode during the follow-up period was excluded. All subjects underwent best corrected visual acuity (BCVA), corneal topography (refractive cylinder, surface regularity index: SRI and surface asymmetry index: SAI), Schirmer I test, tear film break-up time (BUT), corneal sensitivity, and fluorescein staining score measurements before as well as 1, 3, 6 and 12 months after keratoplasty. The relation between the tear functions and the duration until the achievement of maximum BCVA was also evaluated. Linear regression analysis was performed to study the statistical significance of the correlations and the time wise change of each examined parameter. RESULTS: SRI, SAI, and BCVA significantly improved after keratoplasty. The postoperative corneal sensitivity was still significantly low even at 12 months postoperatively. Postoperative BCVA at 3, 6 months and maximum BCVA showed a significant linear negative correlation with the preoperative BUT (3 months; r = -0.461, p = 0.036, 6 months; r = -0.494, p = 0.023, maximum BCVA; r = -0.473, p = 0.030). The duration until the achievement of maximum BCVA showed a significant negative correlation with the preoperative Schirmer test (r = -0.429, p = 0.036). BCVA at 1 and 3 months postoperatively showed significant linear negative correlations with BUT value at the respective periods (1 month; r = -0.665, p = 0.0036, 3 months; r = -0.580, p = 0.0059). CONCLUSION: Preoperative tear functions appeared to have an influence on postoperative BCVA and the duration of visual recovery in keratoconus patients undergoing keratoplasty. Postoperative tear film stability appears to play an important role for obtaining a better BCVA in the early postoperative period after keratoplasty.

Preliminary report of tolvaptan treatment in Japanese patients with heart failure.

While diuretic drugs are commonly used in patients with congestive heart failure, the efficacy of their long-term use still remains controversial. Recently, a new class of diuretics, vasopressin receptor 2 antagonists, has been launched, and tolvaptan is one such drug. We describe our initial experience with this novel agent. Tolvaptan is potentially useful for treatment of heart failure patients with fluid overload who are refractory to conventional diuretic therapies.

[A quality of life questionnaire for Japanese allergic conjunctival disease].

PURPOSE: To establish a specific quality of life (QOL) questionnaire for Japanese allergic conjunctival disease (ACD) (Japanese allergic conjunctival disease QOL questionnaire: JACQLQ). SUBJECTS AND METHODS: A multicenter study was conducted in 521 patients with ACD and 127 healthy volunteers (total 648 cases). The JACQLQ ver. 0 was developed by modifying the Japanese rhino-conjunctivitis QOL questionnaire (JRQLQ). The participants were asked to complete the questionnaire, and objective scores were determined by an ophthalmologist using a slit lamp. To confirm validity, item and factor analyses were conducted and correlation coefficients were calculated. RESULTS: The items were grouped into four subscales (Daily activity, Psychological well-being, Eye symptoms, Nasal symptoms) after factor analysis. The JACQLQ had good item-internal consistency (Cronbach's alpha: 0.846-0.934). QOL scores were correlated with eye itching, eye irritation and tearing. Objective scores were correlated with eye redness, eye itching and eye irritation. Face scores were correlated with eye itching, eye irritation and eye redness. CONCLUSION: The JACQLQ is a useful tool for assessing disease specific QOL in ACD.

[Risk factors of severe peripheral corneal ulcers].

PURPOSE: To evaluate the risk factors of severe peripheral corneal ulcers. PATIENTS AND METHODS: Twenty three eyes of 15 patients (9 eyes of 7 men and 14 eyes of 8 women) with severe peripheral corneal ulcers, who were treated during the past 10 years at Keio University Hospital, were reviewed about the original disease, status of ulcer, treatment, and visual prognosis. RESULTS: Fifteen eyes of 10 patients with Mooren's ulcer, 4 eyes of 3 patients with rheumatoid arthritis, and 4 eyes of 2 patients with Terrien corneal degeneration were included. Mooren's ulcer tends to advance widely. Systemic administration of immunosuppressive and corticosteroidal agents was required in addition to surgical treatment. Visual prognosis was poor in the Mooren's ulcer and perforated cases. CONCLUSION: Mooren's ulcer and perforated cases are risk factors in peripheral corneal ulcer.

Analysis of the Association between Galectin-3 Concentration in Tears and the Severity of Dry Eye Disease: A Case-Control Study.

This study aimed to investigate the relationship between the severity of dry eye disease (DED) and galectin-3 concentration (gal-3) and its cleavage (gal-3C) in tear fluid. Twenty-eight DED patients and 14 controls were recruited at Keio University Hospital. The lissamine green conjunctival staining (LG) score, fluorescein corneal staining (FL) score, tear film break-up time (TBUT), Schirmer's test, and ocular symptoms questionnaire score (dry eye questionnaire score, DEQS) were evaluated. Furthermore, the correlation between these parameters and the concentrations of gal-3 in tears (ng/µg) and the detection rate of gal-3C (%) were analyzed. Gal-3 concentration in tears was positively correlated with the LG score (R = 0.60, p < 0.01), FL score (R = 0.49, p < 0.01), and DEQS (R = 0.45, p < 0.01), and negatively correlated with the TBUT score (R = -0.40, p < 0.01) and Schirmer's I value (R = -0.36, p < 0.01). The detection rate of gal-3C in tears was significantly associated with the severity of DED, especially with the LG (p < 0.01) and FL (p < 0.01) scores. Therefore, the concentration of gal-3 and the detection rate of gal-3C in tears had a significant relationship with the severity of ocular surface barrier disruption.

The effects of a steam warming eye mask on the ocular surface and mental health.

PURPOSE: The continuous use of warming eye masks improves tear function. In this double-blind randomized controlled trial, we aimed to analyze the effects of warming eye mask use on the ocular surface and mental health. METHODS: We enrolled 86 participants (age range: 23-89 years) from affiliated institutions who were divided into two groups: the warm group that used warming eye masks that generate moist heat at 40 °C for 10 min and the control group that used non-warming eye masks. The participants used the masks for 10 min once daily for 2 weeks. Before and after the intervention, in 79 participants (warm group 39, control group 40), we analyzed the tear break up time (TBUT) and corneal and conjunctival fluorescein staining results in the right eye and Hospital Anxiety and Depression Score (Anxiety: HADS-A, Depression: HADS-D), and Subjective Happiness Scale (SHS) questionnaires. The parameters before and after the intervention were compared via paired-t tests. RESULTS: The following variables changed after the intervention: TBUT (warm group: 1.4 ± 2.1 s vs. control group: -0.01 ± 2.38 s), fluorescein staining score (-0.7 ± 1.1 vs.-0.2 ± 1.1), HADS-A (-0.8 ± 3.1 vs. -0.2 ± 2.2), and HADS-D (-1.0 ± 2.4 vs. -0.4 ± 1.9). Significant changes were observed in the TBUT (warm group), fluorescein staining score (warm group), and HADS-D (warm group). CONCLUSIONS: Using a warming eye mask improves not only the ocular surface conditions but also the subjective depression scores.

Myopia, corneal endothelial cell density and morphology in a Japanese population-based cross-sectional study: the JPHC-NEXT Eye Study.

This population-based cross-sectional study was performed to determine the mean corneal endothelial cell density (ECD), coefficient of variation (CV), and hexagonality (HEX), and their associations with myopia in Japanese adults living in Chikusei city. Of 7109 participants with available data, 5713 (2331 male and 3382 female) participants were eligible for analysis. After assessing the relationship between participant characteristics and spherical equivalent refraction (SER), the association of SER with the abnormal value of ECD (< 2000 cells/mm), CV (≥ 0.40), and HEX (≤ 50%) were determined using the logistic regression models adjusting for potential confounders (age, intraocular pressure, keratometric power, height, and antihypertensive drug use). In male participants, there was no statistically significant relationships between SER and endothelial parameters. In female participants, compared to emmetropia, SER ≤ - 6 D had significantly higher odds ratio (OR) of having the abnormal value of CV (OR = 2.07, 95% confidence interval [CI] 1.39-3.10) and HEX (OR = 2.04, 95% CI 1.29-3.23), adjusted for potential confounders, indicating that the high myopia was associated with the abnormal values of CV and HEX. Further adjustment for contact lenses wear partly attenuated these associations. Association between the SER and ECD was not detected.

Efficacy of renal revascularization in a patient with fibromuscular renal artery stenosis and heart failure.

We report the case of a 65-year-old woman with a solitary kidney who developed hypertension due to renal artery stenosis caused by fibromuscular dysplasia. In addition, an echocardiogram revealed severe left ventricular systolic and diastolic dysfunction. Despite antihypertensive drug treatment that included diuretics, her serum concentration of brain natriuretic peptide was persistently elevated and associated with progressive worsening of renal function. She underwent iliac artery to renal artery bypass grafting. After the surgery, blood pressure control was good, the serum concentration of brain natriuretic peptide decreased, and left ventricular diastolic function improved. This case exemplifies the efficacy of renal revascularization in patients with fibromuscular renal artery stenosis and heart failure.

Conjunctival Epithelial Ingrowth After Penetrating Keratoplasty.

PURPOSE: To report a case of conjunctival epithelial ingrowth after penetrating keratoplasty. METHODS: A 57-year-old woman with herpetic corneal keratitis, endotheliitis, and bullous keratopathy underwent penetrating keratoplasty (PKP) and secondary cataract surgery. One month after cataract surgery, an epithelial ingrowth was observed at the 5 o'clock donor host junction. Ingrowth extended into the anterior chamber and along the iris surface by 9 months. Another PKP was performed, and the excised graft was submitted for histopathology. RESULTS: The graft showed CK13-positive and CK3-negative cells lining the endothelial surface, indicating the conjunctival origin of ingrown epithelium. Ten months postoperatively, no recurrence of ingrowth was observed. CONCLUSIONS: We experienced a rare case of conjunctival epithelial ingrowth after penetrating keratoplasty. There was no recurrence of the ingrowth after surgical removal, and the conjunctival origin may explain the relatively benign course of the complication.

Changes in Distribution of Dry Eye Diagnostic Status Among Visual Display Terminal Workers According to the Revised Criteria of the Asia Dry Eye Society.

PURPOSE: The present study aimed to compare the prevalence of dry eye disease (DED) among visual display terminal users using the revised and previous DED criteria. METHODS: This cross-sectional study included 561 participants (187 women). RESULTS: The distribution of diagnostic status according to the previous DED criteria was as follows: definite DED (n = 65, 11.6%), probable DED (n = 303, 54.0%), and non-DED (n = 193, 34.4%). According to the revised criteria, 329 participants (58.6%) were classified as DED and 232 participants (41.4%) were classified as non-DED. CONCLUSIONS: The prevalence of DED among visual display terminal users has increased to 58.6% from 11.6%, according to the revised DED diagnostic criteria of the Asia Dry Eye Society.

Prognosis after lamellar keratoplasty for limbal dermoids using preserved corneas.

PURPOSE: To evaluate the safety and efficacy of lamellar keratoplasty using preserved donor corneas to treat limbal dermoids. STUDY DESIGN: Retrospective study. METHODS: The clinical records of 19 patients with limbal dermoids, who underwent lamellar keratoplasty using preserved corneas that were observed for more than 6 months at the Keio University School of Medicine between January, 2000 and December, 2017, were retrospectively reviewed. We retrospectively analyzed demographics, surgical outcomes, the occurrence of any surgically induced changes in refraction, and intra and postoperative complications. RESULTS: Patient age at surgery showed 2 peaks, the first ranged from 0 to 6 years, and the second from 13 to 20 years. All patients except one had good cosmetic results. Preoperative astigmatism was more than 2 diopters in 12 of 16 eyes for which refractive data were recorded. The refractive cylinder in 8 of the 16 eyes differed after surgery by less than 2 diopters. Treatment of amblyopia by occlusion of the fellow eye and spectacle prescription was done either prior to or following surgery, and resulted in improved visual acuity in 7 patients. Intraoperative complications did not occur in any of the patients. Postoperatively, all patients except one showed corneal re-epithelialization within a week. CONCLUSION: Lamellar keratoplasty using preserved corneas for limbal dermoid yields good cosmetic results. However, improvements in astigmatism and visual acuity are not guaranteed. Preoperative treatment of amblyopia gives a better prognosis for improved visual acuity postoperatively. Long-term observation including amblyopia treatment is required before and after surgery.

Treatment Trends in Dry Eye Disease and Factors Associated with Ophthalmic Follow-up Discontinuation in Japan.

Despite the importance of dry eye disease (DED) treatment, the rate of DED treatment discontinuation, especially discontinuation of ophthalmic follow-up, remains unknown. This study aimed to assess the prevalence and risk factors of ophthalmic follow-up discontinuation for DED. A cross-sectional survey of 1030 participants was conducted using a self-administered web-survey instrument. We collected lifestyle information, history of DED diagnosis, types of treatment, frequency of eye-drop usage, symptoms, and the reasons for discontinuing treatment. Statistical analyses including logistic regression were used to evaluate the risk factors of discontinuing ophthalmic follow-up for DED. A past history of clinical DED diagnosis was reported by 155 (15.0%) subjects. Of those, 130 had persistent DED, and 88 (67.7%) of the subjects reported discontinuation of ophthalmic follow-up for DED. The most prevalent reasons for ophthalmic follow-up discontinuation were time restrictions, followed by dissatisfaction with the DED treatment. Duration after DED diagnosis was the only significant risk factor for discontinuing ophthalmic follow-up after adjusting for age and sex (odds ratio = 1.09, 95% confidence interval = 1.02-1.17, p = 0.009). In conclusion, longer DED duration after diagnosis was a significant risk factor for discontinuing ophthalmic follow-up for DED. This study showed that DED ophthalmic follow-up discontinuation involves both medical and non-medical reasons. Clinicians need to be aware of them, and preventative effort is needed to avoid discontinuation.