Professor Dyfrig Hughes

Athro mewn Ffarmacoeconomeg / Cyfarwyddwr Ymchwil

  1. Erthygl › Ymchwil › Adolygwyd gan gymheiriaid
  2. Cyhoeddwyd

    Economic evaluation of a behavior-modifying intervention to enhance antiepileptic drug adherence

    Hughes, D., Plumpton, C. O., Brown, I., Reuber, M., Marson, A. G. & Hughes, D. A., 26 Maw 2015, Yn: Epilepsy and Behavior. 45, t. 180-186

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  3. Cyhoeddwyd

    Economic evaluations during early (Phase II) drug development: A role for clinical trial simulations.

    Hughes, D., Hughes, D. A. & Walley, T., 1 Ion 2001, Yn: Pharmacoeconomics. 19, 11, t. 1069-1077

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  4. Cyhoeddwyd

    Economic impact of poor compliance with pharmaceuticals.

    Hughes, D. & Hughes, D. A., 1 Awst 2002, Yn: Expert Review of Pharmacoeconomics and Outcomes Research. 2, 4, t. 327-335

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  5. Cyhoeddwyd

    Economics of pharmacogenetic guided treatments: Underwhelming or overstated?

    Hughes, D., Mai 2018, Yn: Clinical Pharmacology and Therapeutics. 103, 5, t. 749-751

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  6. Cyhoeddwyd

    Effectiveness of out-patient based acute heart failure care: A pilot randomised controlled trial

    Wong, K. Y. K., Hughes, D., Debski, M., Latt, N., Assaf, O., Abdelrahman, A., Taylor, R., Allgar, V., McNeill, L., Howard, S., Wong, S. Y. S., Jones, R., Cassidy, C. J., Seed, A., Galasko, G., Clark, A., Davis, G. K., Montasem, A., Lang, C. C., Kalra, P. R., Campbell, R., Lip, G. Y. H. & Cleland, J. G. F., Hyd 2023, Yn: Acta Cardiologica. 78, 7, t. 828-837 10 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  7. Cyhoeddwyd

    Effects of the abolition of prescription charges in Wales: a preliminary analysis.

    Hughes, D., Cohen, D., Alam, M. F., Hughes, D. A., Dunstan, F. & Routledge, P., 1 Ion 2008, Yn: International Journal of Pharmacy Practice. 16, Supplement 1, t. A39

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  8. Cyhoeddwyd

    EstablishINg the best STEp-up treatments for children with uncontrolled asthma despite INhaled corticosteroids (EINSTEIN): Protocol for a systematic review, network meta-analysis and cost-effectiveness analysis using individual participant data (IPD)

    Cividini, S., Sinha, I., Donegan, S., Maden, M., Culeddu, G., Rose, K., Fulton, O., Hughes, D., Turner, S. & Smith, C. T., 5 Chwef 2021, Yn: BMJ Open. 11, e040528.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  9. Cyhoeddwyd

    Estimating Drug Costs in Economic Evaluations in Ireland and the UK: An Analysis of Practice and Research Recommendations.

    Hughes, D., Hughes, D. A., Tilson, L. & Drummond, M. F., 1 Mai 2009, Yn: Pharmacoeconomics. 27, 8, t. 635-643

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  10. Cyhoeddwyd

    Estimation of the impact of noncompliance on pharmacokinetics: an analysis of the influence of dosing regimens

    Hughes, D. & Hughes, D. A., 1 Rhag 2008, Yn: British Journal of Clinical Pharmacology. 65, 6, t. 871-878

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  11. Cyhoeddwyd

    Evaluation of a consultant audit and feedback programme to improve the quality of antimicrobial prescribing in acute medical admissions

    Hughes, D., Roberts, E., Dawoud, D. M., Hughes, D. A. & Cefai, C., 1 Hyd 2015, Yn: International Journal of Pharmacy Practice. 23, 5, t. 333-339

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  12. Cyhoeddwyd

    Experiences of men who have sex with men when initiating, implementing, and persisting with HIV pre-exposure prophylaxis

    Gillespie, D., Wood, F., Williams, A., Ma, R., de Bruin, M., Hughes, D., Jones, A. T., Couzens, Z. & Hood, K., Awst 2022, Yn: Health Expectations. 25, 4, t. 1332-1341 10 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  13. Cyhoeddwyd

    Extended-release pharmacotherapy for opioid use disorder (EXPO): protocol for an open-label randomised controlled trial of the effectiveness and cost-effectiveness of injectable buprenorphine versus sublingual tablet buprenorphine and oral liquid methadone

    Marsden, J., Kelleher, M., Hoare, Z., Hughes, D., Bisla, J., Cape, A., Cowden, F., Day, E., Dewhurst, J., Evans, R., Hearn, A., Kelly, J., Lowry, N., McCusker, M., Murphy, C., Murray, R., Myton, T., Quarshie, S., Scott, G., Turner, S., Vanderwaal, R., Wareham, A., Gilvarry, E. & Mitcheson, L., 19 Awst 2022, Yn: Trials. 23, 1, 697.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  14. Cyhoeddwyd

    Factors influencing user choices to visit either general practitioners or community pharmacists for minor ailments – a discrete choice experiment

    Hughes, D., Hughes, D. A., Myles, S., Longo, M., Lisles, C. & Hood, K., 1 Ion 2007, Yn: Value in Health. 10, 3, t. A23

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  15. Cyhoeddwyd

    Feasibility, validity and reliability of the Welsh version of the EQ-5D health status questionnaire.

    Hughes, D. & Hughes, D. A., 1 Hyd 2007, Yn: Quality of Life Research. 16, 8, t. 1419-1423

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  16. Cyhoeddwyd

    Feasibility, validity, and reliability of the Welsh version of the EQ-5D health status questionnaire

    Hughes, D. & Hughes, D. A., 1 Ion 2007, Yn: Value in Health. 10, 3, t. A189

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  17. Cyhoeddwyd

    Folate Augmentation of Treatment – Evaluation for Depression (FolATED): protocol of a randomised controlled trial.

    Russell, I. T., Slegg, G. P., Roberts, S. H., Bedson, E., Hughes, D., Lloyd, K., Moat, S., Pirmohamed, M., Slegg, G., Tranter, R., Whitaker, R., Wilkinson, C. & Russell, I., 15 Tach 2007, Yn: BMC Psychiatry. 7, 1, t. 65

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  18. Cyhoeddwyd

    Folate Augmentation of Treatment-Evaluation for Depression (FolATED): randomised trial and economic evaluation

    Bedson, E., Bell, D., Carr, D., Carter, B., Hughes, D., Jorgensen, A., Lewis, H., Lloyd, K., McCaddon, A., Moat, S., Pink, J., Pirmohamed, M., Roberts, S., Russell, I., Sylvestre, Y., Tranter, R., Whitaker, R., Wilkinson, C. & Williams, N., Gorff 2014, Yn: Health Technology Assessment. 18, 48, t. 1-159

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  19. Cyhoeddwyd

    Follow-up of cancer in primary care versus secondary care: systematic review

    Lewis, R. A., Neal, R. D., Williams, N. H., France, B., Hendry, M., Russell, D., Hughes, D. A., Russell, I., Stuart, N. S. A., Weller, D. & Wilkinson, C., 1 Gorff 2009, Yn: British Journal of General Practice. 59, 564, t. e234-e247

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  20. Cyhoeddwyd

    From NCE to NICE: the role of pharmacoeconomics

    Hughes, D. & Hughes, D. A., 1 Medi 2010, Yn: British Journal of Clinical Pharmacology. 70, 3, t. 317-319

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  21. Cyhoeddwyd

    Generalisability and Cost-Impact of Antibiotic-Impregnated Central Venous Catheters for Reducing Risk of Bloodstream Infection in Paediatric Intensive Care Units in England

    Harron, K., Mok, Q., Hughes, D., Muller-Pebody, B., Parslow, R., Ramnarayan, P. & Gilbert, R., 21 Maw 2016, Yn: PLoS ONE. 11, 3, t. e0151348

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  22. Cyhoeddwyd

    Generic and therapeutic substitutions in the UK: are they a good thing?

    Hughes, D., Duerden, M. G. & Hughes, D. A., 1 Medi 2010, Yn: British Journal of Clinical Pharmacology. 70, 3, t. 335-341

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  23. Cyhoeddwyd

    Genetic and environmental factors determining clinical outcomes and cost of warfarin therapy: a prospective study.

    Hughes, D., Jorgensen, A. L., Al-Zubiedi, S., Zhang, J. E., Keniry, A., Hanson, A., Hughes, D. A., Van Eker, D., Stevens, L., Hawkins, K., Toh, C. H., Kamali, F., Daly, A. K., Fitzmaurice, D., Coffey, A., Williamson, P. R., Park, B. K., Deloukas, P. & Pirmohamed, M., 1 Hyd 2009, Yn: Pharmacogenetics and Genomics. 19, 10, t. 800-812

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  24. Cyhoeddwyd

    HLA-B*5701 and abacavir hypersensitivity - Reply.

    Hughes, D., Hughes, D. A., Park, B. K. & Pirmohamed, M., 1 Tach 2004, Yn: Pharmacogenetics. 14, 11, t. 784

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  25. Cyhoeddwyd

    HTAs and rare diseases: How to assess their cost-effectiveness

    Hughes, D., Phillips, C. J. & Hughes, D. A., 1 Tach 2011, Yn: Pharmaceuticals Policy and Law. 13, 3-4, t. 161-165

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  26. Cyhoeddwyd

    Health utilities and costs for Motor Neurone Disease

    Moore, A., Young, C. A. & Hughes, D., Tach 2019, Yn: Value in Health. 22, 11, t. 1257-1265

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  27. Cyhoeddwyd

    Health utilities and costs for neuromyelitis optica spectrum disorder

    Hughes, D., Bourke, S., Jones, A., Bhatt, R., Huda, S., Mutch, K. & Jacob, A., 2022, Yn: Orphanet Journal of Rare Diseases. 17, 11 t., 159.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  28. Cyhoeddwyd

    Health utilities and quality-adjusted life years for patients with amyotrophic lateral sclerosis receiving reldesemtiv or placebo in FORTITUDE-ALS

    Gebrehiwet, P., Meng, L., Saroccoa, P., Wei, J., Wolff, A. A., Butzner, M., Chio, A., Andrews, J. A., Genge, A., Hughes, D., Jackson, C. E., Lechtzin, N., Miller, T. M. & Shefner, J. M., 31 Maw 2023, Yn: Journal of Medical Economics. 26, 1, t. 488-493 6 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  29. Cyhoeddwyd

    Identification and Assessment of Adherence-Enhancing Interventions in Studies Assessing Medication Adherence Through Electronically Compiled Drug Dosing Histories: A Systematic Literature Review and Meta-Analysis

    Hughes, D., Holmes, E. A., Demonceau, J., Ruppar, T., Kristano, P., Hughes, A. D., Fargher, E., Przemyslaw, K., De Geest, S., Dobbels, F., Lewek, P., Urquhart, J. & Vrijens, B., 1 Mai 2013, Yn: Drugs. 73, 6, t. 545-562

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  30. Cyhoeddwyd

    Impact of Interventions on Medication Adherence and Blood Pressure Control in Patients with Essential Hypertension: A Systematic Review by the ISPOR Medication Adherence and Persistence Special Interest Group

    Hughes, D., Gwadry-Sridhar, F. H., Manias, E., Lal, L., Salas, M., Hughes, D. A., Ratzki-Leewing, A. & Grubisic, M., 1 Gorff 2013, Yn: Value in Health. 16, 5, t. 863-871

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  31. Cyhoeddwyd

    Impact of non-adherence and flare resolution on the cost effectiveness of treatments for gout: Application of a linked pharmacometric/pharmacoeconomic model

    Hill-McManus, D., Marshall, S., Soto, E., Lane, S. & Hughes, D., Rhag 2018, Yn: Value in Health. 21, 12, t. 1373-1381

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  32. Cyhoeddwyd

    Impact of non-adherence on the safety and efficacy of uric acid lowering therapies in the treatment of gout

    Hill McManus, D., Soto, E., Marshall, S., Lane, S. & Hughes, D., Ion 2018, Yn: British Journal of Clinical Pharmacology. 84, 1, t. 142-152

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  33. Cyhoeddwyd

    Impact of non-compliance on the cost-effectiveness of statin therapy

    Hughes, D., Hughes, D. A. & Bagust, A., 1 Medi 2001, Yn: Value in Health. 4, 6, t. 489

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  34. Cyhoeddwyd

    Impact of relaxing Covid-19 social distancing measures on rural North Wales: a simulation analysis

    Hughes, R. P. & Hughes, D., 14 Rhag 2020, Yn: Frontiers in Public Health. 8, 562473.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  35. Cyhoeddwyd

    Impact on the phased abolition of co-payments on the utilisation of selected prescription medicines in Wales

    Alam, M. F., Cohen, D., Dunstan, F., Hughes, D. & Routledge, P. A., Ion 2018, Yn: Health Economics. 27, 1, t. 236-243

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  36. Cyhoeddwyd

    Impregnated central venous catheters for prevention of bloodstream infection in children (the CATCH trial): a randomised controlled trial

    Gilbert, R. E., Mok, Q., Dwan, K., Harron, K., Moitt, T., Millar, M., Ramnarayan, P., Tibby, S. M., Hughes, D. & Gamble, C. F., 23 Ebr 2016, Yn: The Lancet. 387, 10029, t. 1732-1742

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  37. Cyhoeddwyd

    Innovation at the Intersection of Clinical Trials and Real-World Data Science to Advance Patient Care

    Swift, B., Jain, L., White, C., Chandrasekaran, V., Bhandari, A., Hughes, D. & Jadhav, P., Medi 2018, Yn: Clinical and Translational Science. 11, 5, t. 450-460 11 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  38. Cyhoeddwyd

    Integration of Pharmacometrics and Pharmacoeconomics to Quantify the Value of Improved Forgiveness to Nonadherence: A Case Study of Novel Xanthine Oxidase Inhibitors for Gout

    Hill McManus, D., Marshall, S., Soto, E. & Hughes, D., Medi 2019, Yn: Clinical Pharmacology and Therapeutics. 106, 3, t. 652-660

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  39. Cyhoeddwyd

    Interventions to improve osteoporosis medication adherence and persistence: a systematic review and literature appraisal by the ISPOR Medication Adherence & Persistence Special Interest Group

    Hughes, D., Linck, P. G., Hiligsmann, M., Salas, M., Hughes, D. A., Manias, E., Gwadry-Sridhar, F. H., Linck, P. & Cowell, W., 1 Rhag 2013, Yn: Osteoporosis International. 24, 12, t. 2907-2918

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  40. Cyhoeddwyd

    Is exercise effective in promoting mental well-being in older age? A systematic review.

    Hughes, D., Linck, P. G., Windle, G., Hughes, D. A., Linck, P., Russell, I. T. & Woods, R. T., 1 Awst 2010, Yn: Aging and Mental Health. 14, 6, t. 652-669

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  41. Cyhoeddwyd

    Is there a role for Natural Desiccated Thyroid in the treatment of levothyroxine unresponsive hypothyroidism? Results from a Consecutive Case Series

    Heald, A., Premawardhana, L., Taylor, P., Okosieme, O., Bangi, T., Devine, H., Livingston, M., Javed, A., Moreno, G. Y. C., Watt, T., Stedman, M. & Hughes, D., 28 Rhag 2021, Yn: International Journal of Clinical Practice. 75, 12, e14967.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  42. Cyhoeddwyd

    Lamotrigine versus levetiracetam or zonisamide for focal epilepsy and valproate versus levetiracetam for generalised and unclassified epilepsy: two SANAD II non-inferiority RCTs

    Marson, A. G., Burnside, G., Appleton, R., Smith, D., Leach, J. P., Sills, G., Tudor-Smith, C., Plumpton, C., Hughes, D., Williamson, P. R., Baker, G., Balabanova, S., Taylor, C., Brown, R., Hindley, D., Howell, S., Maguire, M., Mohanraj, R. & Smith, P. E., Rhag 2021, Yn: Health Technology Assessment. 25, 75, 162 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  43. Cyhoeddwyd

    Less is more: Medicines that require less frequent administration improve adherence, but are they better?

    Hughes, D. & Hughes, D. A., 1 Ion 2006, Yn: Pharmacoeconomics. 24, 3, t. 211-213

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  44. Cyhoeddwyd

    Lessons learnt from a discontinued randomised controlled trial: Adalimumab injection compared with placebo for patients receiving physiotherapy treatment for sciatica (Subcutaneous Injection of Adalimumab Trial compared with Control: SCIATiC)

    Williams, N., Jenkins, A., Goulden, N., Hoare, Z., Hughes, D., Wood, E., Foster, N. E., Walsh, D. A., Carnes, D., Sparkes, V., Hay, E. M., Isaacs, J., Konstantinou, K., Morrissey, D., Karppinen, J., Genevay, S. & Wilkinson, C., 31 Gorff 2018, Yn: Trials. 19, 408.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  45. Cyhoeddwyd

    Linked Pharmacometric-Pharmacoeconomic Modeling and Simulation in Clinical Drug Development

    Hill-McManus, D., Marshall, S., Liu, J., Willke, R. & Hughes, D., Gorff 2021, Yn: Clinical Pharmacology and Therapeutics. 110, 1, t. 49-63

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  46. Cyhoeddwyd

    Liothyronine for hypothyroidism: A candidate for disinvestment or in need of further research? A value of information analysis

    Hughes, D., Skiadas, K., Fitzsimmons, D., Anderson, P. & Heald, A., 3 Rhag 2021, Yn: BMJ Open. 11, 12, e051702.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  47. Cyhoeddwyd

    Managing Access to Advanced Therapy Medicinal Products: Challenges for NHS Wales

    Champion, A. R., Lewis, S., Davies, S. & Hughes, D., Meh 2021, Yn: British Journal of Clinical Pharmacology. 87, 6, t. 2444-2449

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  48. Cyhoeddwyd

    Mapping ALSFRS-R and ALSUI to EQ-5D in patients with motor neurone disease

    Moore, A., Young, C. A. & Hughes, D., Tach 2018, Yn: Value in Health. 21, 11, t. 1322-1329

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  49. Cyhoeddwyd

    Measurement of adherence, drug concentrations and the effectiveness of artemether-lumefantrine, chlorproguanil-dapsone or sulphadoxine-pyrimethamine in the treatment of uncomplicated malaria in Malawi.

    Hughes, D., Bell, D. J., Wootton, D., Mukaka, M., Montgomery, J., Kayange, N., Chimpeni, P., Hughes, D. A., Molyneux, M. E., Ward, S. A., Winstanley, P. A. & Lalloo, D. G., 26 Awst 2009, Yn: Malaria Journal. 8, t. 204

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  50. Cyhoeddwyd

    Mechanism-Based Approach to the Economic Evaluation of Pharmaceuticals: Pharmacokinetic/Pharmacodynamic/Pharmacoeconomic Analysis of Rituximab for Follicular Lymphoma.

    Hughes, D., Pink, J., Lane, S. & Hughes, D. A., 19 Maw 2012, Yn: Pharmacoeconomics.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  51. Cyhoeddwyd

    Mechanistically informed non-invasive peripheral nerve stimulation for peripheral neuropathic pain: a randomised double-blind sham-controlled trial

    Johnson, S., Marshall, A., Hughes, D., Holmes, E., Henrich, F., Nurmikko, T., Sharma, M., Frank, B., Bassett, P., Marshall, A. & Goebel, A., 6 Tach 2021, Yn: Journal of Translational Medicine. 19, 1, 458.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid