High prevalence of distal sensory polyneuropathy in antiretroviral-treated and untreated people with HIV in Tanzania

Global Prevalence of Chronic Pain in Women with HIV: A Systematic Review and Meta-analysis

Chronic pain is common among people with human immunodeficiency virus (HIV) and detrimental to quality of life and overall health. It is often underdiagnosed, undertreated, and frankly dismissed in women with HIV, despite growing evidence that it is highly prevalent in this population. Thus, we conducted a systematic review and meta-analysis to estimate the global prevalence of chronic pain in women with HIV. The full protocol can be found on PROSPERO (identifier CRD42022301145). Of the 2984 references identified in our search, 36 were included in the systematic review and 35 in the meta-analysis. The prevalence of chronic pain was 31.2% (95% confidence interval [CI], 24.6%-38.7%; I2 = 98% [95% CI, 97%-99%]; P < .0001). In this global assessment, we found a high prevalence of chronic pain among women with HIV, underscoring the importance of understanding the etiology of chronic pain, identifying effective treatments, and conducting regular assessments in clinical practice.

Neuropathy in Human Immunodeficiency Virus: A Review of the Underlying Pathogenesis and Treatment

This article explores the various causes of the human immunodeficiency virus (HIV), and its associated neuropathy, including the effects of HIV on the nervous system and the long-standing therapy that is often provided to patients with HIV. Several studies regarding the neurotoxic effects of combined antiretroviral therapy (cART) and HIV were reviewed and various hypotheses were discussed. Furthermore, we present the nature of HIV-sensory neuropathy (HIV-SN) among different demographic populations and their subsequent risk factors predisposing them to this condition. It was observed that the incidence of the disease increases in increased survival of the patients as well as in males. Finally, the current approach to HIV-SN and its overlapping features with other causes of peripheral neuropathy have been discussed which demonstrates that a clinical examination is the most important clue for a healthcare professional to suspect the disease. Our main aim was to study the current perspectives and guidelines for diagnosing and managing a patient with HIV-SN to reduce disease prevalence and bring about a more aware frame of mind when following up with an HIV patient.

Magnitude of Peripheral Sensory Neuropathy and Associated Factors Among HIV/AIDS Clients Receiving Care at Public Health Institutions, Northwest Ethiopia

Background: In the mid-1990s, the development of combination antiretroviral therapy converted HIV infection into a chronic condition, with newly diagnosed patients now living longer than the general population. HIV affects both the central and peripheral nerve systems, resulting in a variety of clinical problems, including peripheral neuropathy, which is a common neurological consequence. Despite this, there is a scarcity of data on the extent of peripheral sensory neuropathy and its underlying factors in Ethiopia, necessitating this study. Objective: The primary goal of this study is to assess the degree of peripheral sensory neuropathy and its related factors among HIV/AIDS clients on follow up at public health institutions in Northwest Ethiopia. Methodology: Institution based cross-sectional study was conducted from November 1 to 30 December 2020 at selected south Gondar zone public health institutions ART clinic. Multistage sampling technique was used to select the study participants. Standardized Questioner adapted from other study was used to collect the data. Moreover, Brief Peripheral Neuropathy Screening tool (BPNS) was used to assess peripheral sensory neuropathy. The data were entered with epi-data manager version 4.4 and analyzed using STATA version 16. Result: A total of 555 adult PLWHIV agreed to participate in the study, resulting in a response rate of 96.8%. The prevalence of Peripheral sensory neuropathy was 32.25, 95% CI (28.28, 36.26). The participant’s age, DM comorbidity, viral load level, and disease clinical stage were all found to have a statistically significant association with peripheral sensory neuropathy. Conclusion: Peripheral sensory neuropathy was incredibly common. Accordingly, peripheral sensory neuropathy was found considerably associated with age, viral load level, stage of the disease, and DM comorbidity. It is vital to integrate routine peripheral sensory neuropathy screening strategies for clients who are on ART follow up for prevention and early identification of the problem.

Clinical Characteristics of Peripheral Neuropathy in Kenyan Patients with HIV Infection Compared with Patients with Concurrent HIV Infection and Diabetes Mellitus

INTRODUCTION

Persons living with human immunodeficiency virus (HIV) are living longer and at risk of non-communicable diseases, including diabetes mellitus (DM). Both HIV and DM place patients at risk of peripheral neuropathy (PN). Our aim was to demonstrate the prevalence and characteristics of PN in our population of patients with HIV infection compared with concomitant HIV and DM.

METHODS

A prospective cross-sectional study was performed at the Aga Khan Hospital in Nairobi, Kenya. Data were collected on demographics and characteristics of DM and HIV. Symptoms and signs of PN were evaluated by Neuropathy Symptom Score, Neuropathy Disability Score, and 10 g monofilament testing.

RESULTS

Two groups were recruited, each consisting of 68 patients: (1) HIV only, (2) HIV and DM. The median age of patients was 51 years (IQR 42.8-58.6) and 55% were male. Median duration for HIV was 10 years (IQR 5-12) with a median CD4 count of 524 cells/mm³ (IQR 369-731). Median duration for DM was 1 year with a median glycosylated hemoglobin of 6.7% (IQR 6.6-7.6). Sixty-nine percent of patients with HIV had suppressed viral loads, and 9 patients (6.6%) had a history neurotoxic antiretroviral therapy use. PN was detected in 11 (16%) HIV-only patients, and in 17 (25%) participants who had both HIV and DM (Fisher exact test chi-square = 0.4). Univariate analysis demonstrated older age, high body mass index, and long duration of HIV were associated with an OR of 1.07 (95% CI 1.02-1.11), 1.21 (95% CI 0.46-3.11), and 1.07 (95% CI 0.99-1.15) in the overall group, respectively.

CONCLUSION

Our study demonstrates a higher but non-significant prevalence of PN in patients with both HIV and DM when compared to HIV alone. HIV disease control had no association with PN presence.

Evaluation of a screening tool for the identification of neurological disorders in rural Uganda

BACKGROUND

Neurological disorders are common in sub-Saharan African, but accurate neuroepidemiologic data are lacking from the region. We assessed a neuroepidemiological screening tool in a rural Ugandan cohort with high HIV prevalence.

METHODS

Participants were recruited from the Rakai Neurology Study in rural Rakai District, Uganda. A nurse administered the tool and a sociodemographic survey. 100 participants returned for validation examinations by a neurologist (validation cohort). The diagnostic utility and validity of the instrument were calculated and characteristics of those with and without neurological disorders compared.

RESULTS

The tool was administered to 392 participants, 48% female, 33% people with HIV, average age 35.1 ± 8.5 years. 33% of the study cohort screened positive for neurologic disorders. These participants were older [mean (SD): 38.3 (9.7) vs. 33.5 (7.1) years, p < 0.001], had a lower Karnofsky score [89.8 (8.4) vs. 93.9 (7.5), p < 0.001] and had a lower body mass index [21.8 (3.3) vs. 22.8 (3.7), p = 0.007] than those who screened negative. Amongst the validation cohort, 54% had a neurological abnormality of which 46% were symptomatic. The tool was 57% sensitive and 74% specific for detecting any neurological abnormality and 80% sensitive and 69% specific for symptomatic abnormalities.

CONCLUSIONS

We found a lower sensitivity and similar specificity for the screening tool compared with two previous studies. The lower validity in this study was likely due in part to the high percentage of asymptomatic neurological abnormalities detected. This screening tool will require further refinement and cultural contextualization before it can be widely implemented across new populations.

Human immunodeficiency virus-related peripheral neuropathy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Human immunodeficiency virus (HIV)-associated neurological syndromes occur in affected individuals as a consequence of primary HIV infection, opportunistic infections, inflammation and as an adverse effect of some forms of antiretroviral treatment (ART). The aim of this systematic review was to establish the epidemiological characteristics, clinical features, pathogenetic mechanisms and risk factors of HIV-related peripheral neuropathy (PN).

METHODS

A systematic, computer-based search was conducted using the PubMed database. Data regarding the above parameters were extracted. Ninety-four articles were included in this review.

RESULTS

The most commonly described clinical presentation of HIV neuropathy is the distal predominantly sensory polyneuropathy. The primary pathology in HIVPN appears to be axonal rather than demyelinating. Age and treatment with medications belonging in the nucleoside analogue reverse transcriptase class are risk factors for developing HIV-related neuropathy. The pooled prevalence of PN in patients naïve to ARTs was established to be 29% (95% CI: 9%-62%) and increased to 38% (95% confidence interval [CI]: 29%-48%) when looking into patients at various stages of their disease. More than half of patients with HIV-related neuropathy are symptomatic (53%, 95% CI: 41%-63%). Management of HIV-related neuropathy is mainly symptomatic, although there is evidence that discontinuation of some types of ART, such as didanosine, can improve or resolve symptoms.

CONCLUSIONS

Human immunodeficiency virus-related neuropathy is common and represents a significant burden in patients' lives. Our understanding of the disease has grown over the last years, but there are unexplored areas requiring further study.

Conditional expression of HIV-1 tat in the mouse alters the onset and progression of tonic, inflammatory and neuropathic hypersensitivity in a sex-dependent manner

BACKGROUND

At least one-third of HIV-1-afflicted individuals experience peripheral neuropathy. Although the underlying mechanisms are not known, they may involve neurotoxic HIV-1 proteins.

METHODS

We assessed the influence of the neurotoxic HIV-1 regulatory protein, Tat, on inflammatory and neuropathic nociceptive behaviours using transgenic male and female mice that conditionally expressed (or did not express) HIV-1 Tat_1-86 in fibrillary acidic protein-expressing glia in the central and peripheral nervous systems.

RESULTS

Tat induction significantly attenuated the time spent paw-licking following formalin injection (2.5%, i.pl.) in both male and female mice. However, significant sex differences were observed in the onset and magnitude of inflammation and sensory sensitivity following complete Freund's adjuvant (CFA) injection (10%, i.pl.) after Tat activation. Unlike female mice, male mice showed a significant attenuation of paw swelling and an absence of mechanical/thermal hypersensitivity in response to CFA after Tat induction. Male Tat(+) mice also showed accelerated recovery from chronic constrictive nerve injury (CCI)-induced neuropathic mechanical and thermal hypersensitivity compared to female Tat(+) mice. Morphine (3.2 mg/kg) fully reversed CCI-induced mechanical hypersensitivity in female Tat(-) mice, but not in Tat(+) females.

CONCLUSIONS

The ability of Tat to decrease oedema, paw swelling, and limit allodynia suggests a sequel of events in which Tat-induced functional deficits precede the onset of mechanical hypersensitivity. Moreover, HIV-1 Tat attenuated responses to inflammatory and neuropathic insults in a sex-dependent manner. HIV-1 Tat appears to directly contribute to HIV sensory neuropathy and reveals sex differences in HIV responsiveness and/or the underlying peripheral neuroinflammatory and nociceptive mechanisms.

Neurological disorders in HIV in Africa: a review

BACKGROUND

Neurological disorders in HIV infection are a common cause of morbidity and mortality. The aim of this paper is to provide a narrative overview of up to date information concerning neurological disorders affecting HIV infected persons in Africa.

METHODS

Seminal research concerning neurological disorders among HIV-infected adults in sub-Saharan Africa from prior to 2000 was combined with an in-depth search of PubMed to identify literature published from 2000 to 2017. The following Mesh terms were used. "Nervous System Diseases" "HIV Infections" and "Africa South of the Sahara" and "Seizures" or "Spinal Cord Diseases" or "Peripheral Nervous System Diseases" or "AIDS Dementia Complex" or "Opportunistic Infections" or "Immune Reconstitution Inflammatory Syndrome" or "Stroke". Only those articles written in English were used. A total of 352 articles were identified, selected and reviewed and 180 were included in the study. These included case series, observational studies, interventional studies, guidelines and reviews with metanalyses. The author also included 15 publications on the subject covering the earlier phase of the HIV epidemic in Africa from 1987 to 1999 making a total of 195 references in the study. This was combined with extensive personal experience diagnosing and treating these neurological disorders.

RESULTS

Neurological disorders were common, typically occurring in WHO stages III/IV. These were in three main categories: those arising from opportunistic processes mostly infections, direct HIV infection and autoimmunity. The most common were those arising from direct HIV infection occurring in >50%. These included HIV-associated neurocognitive dysfunction (HAND), neuropathy and myelopathy. Opportunistic infections occurred in >20% and frequently had a 6-9-month mortality rate of 60-70%. The main causes were cryptococcus, tuberculosis, toxoplasmosis and acute bacterial meningitis. Concurrent systemic tuberculosis occurred in almost 50%.

CONCLUSION

Neurological disorders are common in HIV in Africa and the main CNS opportunistic infections result in high mortality rates. Strategies aimed at reducing their high burden, morbidity and mortality include early HIV diagnosis and anti-retroviral therapy (ART), screening and chemoprophylaxis of main opportunistic infections, improved clinical diagnosis and management and programme strengthening.

Epidemiology and factors associated with peripheral neuropathy among HIV infected patients in Gondar, Ethiopia: A cross-sectional study

Background

Antiretroviral therapy has surely increased the life expectancy of people living with HIV. However, long term complications like HIV associated sensory neuropathy has a negative impact on quality of life among people living with HIV (PLHIV). In Ethiopia, lack of data on magnitude of the burden and predictors of HIV associated sensory neuropathy in many resource limited setting has led to under diagnosis and eventually under management of HIV-SN. Hence, this study was set out to establish the burden of HIV-associated sensory neuropathy and, its association with demographic, health and clinical characteristics among people living with HIV in Ethiopia.

Methods

Cross-sectional study was conducted to assess the prevalence of HIV-associated sensory neuropathy and the associated factors among adult HIV patients at University of Gondar Teaching Hospital, Gondar, Ethiopia. Brief Peripheral Neuropathy Screening tool validated by AIDs Clinical trial group was used for screening HIV-associated sensory neuropathy. Data were analyzed descriptively and through uni- and multivariate logistic regression.

Results

In total 359 adult PLHIV with a mean age of 36.5± 9.07 years participated, their median duration of HIV infection was 60 months (IQR 36–84) and their median CD4 count 143cells/μL (IQR 69.5–201.5). Age above 40 years, anti-tuberculosis regimen, tallness, and exposure to didanosine contained antiretroviral therapy were found to be associated with HIV-associated sensory neuropathy (AOR 1.82, 1.84, 1.98 and 4.33 respectively).

Conclusions

More than half of the HIV patients who attended HIV care clinic at University of Gondar hospital during the study period were found to present with peripheral sensory neuropathy. Higher age, tallness, TB medication, and didanosine in ART were significantly associated with HIV-SN as screened by effective diagnostic (BPNS) tool.

Reduced intraepidermal nerve fibre density, glial activation, and sensory changes in HIV type-1 Tat-expressing female mice: involvement of Tat during early stages of HIV-associated painful sensory neuropathy

INTRODUCTION

HIV infection is associated with chronic pain states, including sensory neuropathy, which affects greater than 40% of patients.

OBJECTIVES AND METHODS

To determine the impact of HIV-Tat induction on nociceptive behaviour in female mice conditionally expressing HIV Tat1-86 protein through a doxycycline (DOX)-driven glial fibrillary acidic protein promoter, intraepidermal nerve fibre density and immune cell activation in the dorsal root ganglion (DRG) and spinal cord were assessed by immunohistochemistry. Mice were assessed for mechanical and thermal sensitivity for 9 weeks using von-Frey and Hargreaves tests.

RESULTS

Intraepidermal nerve fibre density was significantly reduced after 6 weeks of Tat induction, similar to sensory neuropathy seen in clinical HIV infection. Tat induction through DOX caused a significant reduction in paw withdrawal thresholds in a time-dependent manner starting the 4th week after Tat induction. No changes in paw withdrawal latencies were seen in Tat(-) control mice lacking the tat transgene. Although reductions in paw withdrawal thresholds increased throughout the study, no significant change in spontaneous motor activity was observed. Spinal cord (cervical and lumbar), DRG, and hind paw skin were collected at 8 days and 6 weeks after Tat induction. HIV-Tat mRNA expression was significantly increased in lumbar DRG and skin samples 8 days after DOX treatment. Tat induced a significant increase in the number of Iba-1 positive cells at 6 weeks, but not after 8 days, of exposure. No differences in glial fibrillary acidic protein immunoreactivity were observed.

CONCLUSION

These results suggest that Tat protein contributes to painful HIV-related sensory neuropathy during the initial stages of the pathogenesis.

Factors associated with distal symmetric polyneuropathies in adult Zambians: A cross-sectional, observational study of the role of HIV, non-antiretroviral medication exposures, and nutrition

BACKGROUND

Non-antiretroviral (ART) drug exposures and poor nutrition may be important modifiable risk factors for distal symmetric polyneuropathies (DSP) in sub-Saharan Africa.

METHODS

We conducted a cross-sectional study of DSP prevalence and factors associated with DSP among clinic attendees in urban and rural Zambia. All participants underwent neurologist-performed examination. Laboratory investigations seeking comorbid risk factors for DSP were performed for DSP cases.

RESULTS

We identified 31/137 (22.6%) HIV+ and 21/177 (11.9%) HIV- DSP cases. DSP prevalence did not differ by urbanicity, although rural participants were significantly more likely to have one asymptomatic DSP sign. Low dietary diversity, history of syphilis, history of tuberculosis, and prior metronidazole and ciprofloxacin use were associated with DSP amongst HIV+ cases, while age and education were associated with DSP in HIV- participants (all p-values < 0·05). In a multivariate logistic regression model, HIV (p = 0·0001) and age (p < 0·0001), and ciprofloxacin exposure (p = 0·01) remained independently associated with DSP. While diabetes was rare, supoptimal micronutrients levels were common among DSP cases regardless of HIV status.

CONCLUSIONS

While HIV infection is strongly associated with DSP in Zambia, history of non-ART drug exposures and low dietary diversity are also important determinants of DSP in HIV+ individuals. Treatable micronutrient deficiencies were common.

Prevalence, incidence and predictors of peripheral neuropathy in African adults with HIV infection within the DART trial

OBJECTIVES

We investigated the prevalence, incidence and predictors of new peripheral neuropathy episodes in previously untreated, symptomatic HIV-infected Ugandan/Zimbabwean adults initiating zidovudine-based antiretroviral therapy (ART).

DESIGN

An open-label, multicentre, randomized trial.

METHODS

Peripheral neuropathy was self-reported at 12-weekly clinic visits. Cox regression models (excluding participants reporting preexisting peripheral neuropathy at ART initiation), considered sex; pre-ART WHO stage, age and CD4(+) cell count; CD4(+) cell count versus no CD4(+) cell count monitoring; and time-updated CD4(+) cell count, weight and use of stavudine, isoniazid and didanosine.

RESULTS

Four hundred and twenty-one out of 3316(13%) patients reported preexisting peripheral neuropathy at ART initiation. Median (interquartile range, IQR) follow-up in 2895 participants without preexisting peripheral neuropathy was 4.9 (4.7-5.4) years. Three hundred and fifty-four (12%) took stavudine as first-line substitution and 518 (18%) took isoniazid during follow-up. Two hundred and ninety (11%) participants developed a new peripheral neuropathy episode, an incidence of 2.12 per 100 person-years. Eighteen (0.1%) had a grade 3/4 episode. Independent predictors of peripheral neuropathy were current stavudine use [adjusted hazard ratio (a)HR 4.16 (95% confidence interval, 95% CI 3.06-5.66], current isoniazid use [aHR 1.59 (95% CI 1.02-2.47)] and current didanosine use [aHR 1.60 (95% CI 1.19-2.14)]. Higher risks were independently associated with higher pre-ART weight [aHR (per+5 kg) 1.07 (95% CI 1.01-1.13)] and older age aHR (per 10 years older) 1.29 (95% CI 1.12-1.49), but there was no significant effect of sex (P = 0.13), pre-ART CD4(+) cell count (P = 0.91) or CD4(+) cell count monitoring (P = 0.73).

CONCLUSION

Current stavudine, didanosine or isoniazid use continue to increase peripheral neuropathy risks, as does older age and weight at ART initiation; however, we found no evidence of increased risk in women in contrast to previous studies. The incidence of peripheral neuropathy may now be lower in ART programmes, as stavudine and didanosine are no longer recommended. All patients receiving isoniazid, either as part of antituberculosis (TB) chemotherapy or TB-preventive therapy, should receive pyridoxine as recommended in national guidelines.

Inadequate pain relief in ambulatory patients with human immunodeficiency virus disease in Port Harcourt

OBJECTIVES

To estimate the prevalence of pain in ambulatory patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) in Port Harcourt and to determine the type, site, severity, and adequacy of the treatment of pain in these patients.

MATERIALS AND METHODS

A cross-sectional survey was carried out at two antiretroviral therapy centers in Port Harcourt, Nigeria. A data sheet, the brief pain inventory, and the short form of the McGill pain questionnaire were used and 157 patients in various stages of HIV/AIDS participated in the study.

RESULTS

About 83.7% (129/157) of the ambulatory patients with HIV/AIDS complained of pains. Of the patients who reported pain 61.24% (79/129) reported nociceptive pain while 38.76% (50/129) reported neuropathic pain. Chest pain was the most frequent site of pain followed by headache. About 82% (106/129) of those who complained of pain received some form of analgesic, but only 23.58% (25/106) of these obtained adequate pain relief. The majority of the participants had significant impairment of their quality of life due to the severity of their pain.

CONCLUSION

Pain associated with significant impairment of quality of life is common in ambulatory patients with HIV/AIDS in Port Harcourt. Whereas the majority of the patients used various pain relief methods, analgesia was inadequate.

Frequency and risk factors for distal sensory polyneuropathy in HIV infection in a developing country

Distal sensory polyneuropathy is a source of morbidity in HIV infection. This study aims to determine the frequency and effect of demographic and clinical variables on distal sensory polyneuropathy, among HIV-positive participants in south-east Nigeria. The study involved highly active antiretroviral therapy (HAART)-naive, patients on HAART and HIV-negative matched controls conducted at the University of Nigeria Teaching Hospital, Enugu south-east Nigeria. Distal sensory polyneuropathy was diagnosed with clinical evaluation and the use of Bio Thesiometer, 10 g monofilament and ankle reflex. There were 100 participants in each of the groups, comprising 109 (36.3%) men and 191 (63.7%) women, with median age of 35 years. About 42.5% (85/200) of the HIV-positive participants (37 drug naive and 48 on HAART) had distal sensory polyneuropathy. None in the control group had distal sensory polyneuropathy. Age ( p = 0.02), height ( p = 0.002), low haemoglobin ( p = 0.03) and mean duration on HAART ( p = 0.006) were significantly associated with distal sensory polyneuropathy, while gender ( p = 0.497), body mass index ( p = 0.657) and CD4 count ( p = 0.482) did not affect distal sensory polyneuropathy. Low haemoglobin, height, and duration on HAART were independent risk factors for distal sensory polyneuropathy. Addressing correctable causes of anaemia, and alternatives to neurotoxic HAART may minimize the risk of distal sensory polyneuropathy.

Manifestations of HIV infection in the peripheral nervous system

Peripheral nerve disorders are associated with all stages of HIV infection. Distal sensory polyneuropathy is characterised by often-disabling pain that is difficult to treat. It is prevalent in both high-income and low-income settings. In low-income settings, use of potentially neurotoxic antiretrovirals, which are inexpensive and widely available, contributes substantially to incidence. Research has focused on identification of factors that predict risk of distal sensory polyneuropathy and elucidation of the multifactorial mechanisms behind pathogenesis. Sensorimotor polyneuropathies and polyradiculopathies are less frequent than distal sensory polyneuropathy, but still occur in low-income settings and have potentially devastating consequences. However, many of these diseases can be treated successfully with a combination of antiretroviral and immune-modulating therapies. To distinguish between peripheral nerve disorders that have diverse, overlapping, and frequently atypical presentations can be challenging; a framework based on a clinicoanatomical approach might assist in the diagnosis and management of such disorders.

Drug-induced neuropathies

Although drug-induced neuropathies account for only 2-4% of referrals, their identification is important. Numerically, chemotherapy and antiretroviral drugs are the most important worldwide. Research is currently focused on elucidating pathogenic mechanisms and the earliest presymptomatic changes using neurophysiological and pharmacogenetic techniques in order to avoid the drug or make dosage changes before irreversible damage occurs. Chemoprotectants against chemotherapy-induced neuropathy are also an active area of research. This chapter focuses on the pathophysiology of drug-induced neuropathies in general, followed by detailed reviews of neuropathy due to; newer compounds such as TNF (tumor necrosis factor) α antagonists and antibiotics such as linezolid; chemotherapeutic agents, old and new, where significant progress has been made; antiretroviral drugs; and amiodarone, which is unusual in that it causes a demyelinating neuropathy. The controversial issue of statin-induced neuropathy is also reviewed.