Get quick answers to your questions about the article from our AI researcher chatbot
{'id': 'https://openalex.org/W1539633218', 'doi': 'https://doi.org/10.1007/s00296-002-0237-4', 'title': 'Age at disease onset and diagnosis delay in HLA-B27 negative vs. positive patients with ankylosing spondylitis', 'display_name': 'Age at disease onset and diagnosis delay in HLA-B27 negative vs. positive patients with ankylosing spondylitis', 'publication_year': 2003, 'publication_date': '2003-03-01', 'ids': {'openalex': 'https://openalex.org/W1539633218', 'doi': 'https://doi.org/10.1007/s00296-002-0237-4', 'mag': '1539633218', 'pmid': 'https://pubmed.ncbi.nlm.nih.gov/12634937'}, 'language': 'en', 'primary_location': {'is_oa': False, 'landing_page_url': 'https://doi.org/10.1007/s00296-002-0237-4', 'pdf_url': None, 'source': {'id': 'https://openalex.org/S50823678', 'display_name': 'Rheumatology International', 'issn_l': '0172-8172', 'issn': ['0172-8172', '1437-160X'], 'is_oa': False, 'is_in_doaj': False, 'is_core': True, 'host_organization': 'https://openalex.org/P4310319900', 'host_organization_name': 'Springer Science+Business Media', 'host_organization_lineage': ['https://openalex.org/P4310319965', 'https://openalex.org/P4310319900'], 'host_organization_lineage_names': ['Springer Nature', 'Springer Science+Business Media'], 'type': 'journal'}, 'license': None, 'license_id': None, 'version': None, 'is_accepted': False, 'is_published': False}, 'type': 'article', 'type_crossref': 'journal-article', 'indexed_in': ['crossref', 'pubmed'], 'open_access': {'is_oa': False, 'oa_status': 'closed', 'oa_url': None, 'any_repository_has_fulltext': False}, 'authorships': [{'author_position': 'first', 'author': {'id': 'https://openalex.org/A5048310205', 'display_name': 'Ernst Feldtkeller', 'orcid': None}, 'institutions': [{'id': 'https://openalex.org/I186563081', 'display_name': 'PE International (Germany)', 'ror': 'https://ror.org/01bss2h67', 'country_code': 'DE', 'type': 'company', 'lineage': ['https://openalex.org/I186563081']}], 'countries': ['DE'], 'is_corresponding': False, 'raw_author_name': 'Ernst Feldtkeller', 'raw_affiliation_strings': ['Ankylosing Spondylitis International Federation, Michaeliburgstraße 15, 81671 Munich, Germany,'], 'affiliations': [{'raw_affiliation_string': 'Ankylosing Spondylitis International Federation, Michaeliburgstraße 15, 81671 Munich, Germany,', 'institution_ids': ['https://openalex.org/I186563081']}]}, {'author_position': 'middle', 'author': {'id': 'https://openalex.org/A5003977860', 'display_name': 'Muhammad A. Khan', 'orcid': 'https://orcid.org/0000-0001-9027-0511'}, 'institutions': [{'id': 'https://openalex.org/I58956616', 'display_name': 'Case Western Reserve University', 'ror': 'https://ror.org/051fd9666', 'country_code': 'US', 'type': 'education', 'lineage': ['https://openalex.org/I58956616']}], 'countries': ['US'], 'is_corresponding': False, 'raw_author_name': 'Muhammad Khan', 'raw_affiliation_strings': ['Case Western Reserve University, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109-1998, USA,'], 'affiliations': [{'raw_affiliation_string': 'Case Western Reserve University, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109-1998, USA,', 'institution_ids': ['https://openalex.org/I58956616']}]}, {'author_position': 'middle', 'author': {'id': 'https://openalex.org/A5104506506', 'display_name': 'Désirée van der Heijde', 'orcid': 'https://orcid.org/0000-0002-5781-158X'}, 'institutions': [{'id': 'https://openalex.org/I2800191616', 'display_name': 'Maastricht University Medical Centre', 'ror': 'https://ror.org/02d9ce178', 'country_code': 'NL', 'type': 'healthcare', 'lineage': ['https://openalex.org/I2800191616']}], 'countries': ['NL'], 'is_corresponding': False, 'raw_author_name': 'Désirée van der Heijde', 'raw_affiliation_strings': ['Department of Medicine, University Hospital Maastricht, Postbus 5800, 6202 AZ Maastricht, The Netherlands,'], 'affiliations': [{'raw_affiliation_string': 'Department of Medicine, University Hospital Maastricht, Postbus 5800, 6202 AZ Maastricht, The Netherlands,', 'institution_ids': ['https://openalex.org/I2800191616']}]}, {'author_position': 'middle', 'author': {'id': 'https://openalex.org/A5001088944', 'display_name': 'Sjef van der Linden', 'orcid': None}, 'institutions': [{'id': 'https://openalex.org/I2800191616', 'display_name': 'Maastricht University Medical Centre', 'ror': 'https://ror.org/02d9ce178', 'country_code': 'NL', 'type': 'healthcare', 'lineage': ['https://openalex.org/I2800191616']}], 'countries': ['NL'], 'is_corresponding': False, 'raw_author_name': 'Sjef van der Linden', 'raw_affiliation_strings': ['Department of Medicine, University Hospital Maastricht, Postbus 5800, 6202 AZ Maastricht, The Netherlands,'], 'affiliations': [{'raw_affiliation_string': 'Department of Medicine, University Hospital Maastricht, Postbus 5800, 6202 AZ Maastricht, The Netherlands,', 'institution_ids': ['https://openalex.org/I2800191616']}]}, {'author_position': 'last', 'author': {'id': 'https://openalex.org/A5069831361', 'display_name': 'Jürgen Braun', 'orcid': 'https://orcid.org/0000-0002-9156-5095'}, 'institutions': [{'id': 'https://openalex.org/I4210091869', 'display_name': 'Rheumazentrum Ruhrgebiet', 'ror': 'https://ror.org/00e03sj10', 'country_code': 'DE', 'type': 'healthcare', 'lineage': ['https://openalex.org/I2799784675', 'https://openalex.org/I4210088550', 'https://openalex.org/I4210091869']}], 'countries': ['DE'], 'is_corresponding': False, 'raw_author_name': 'Jürgen Braun', 'raw_affiliation_strings': ['Rheumazentrum Ruhrgebiet, St.-Josefs-Krankenhaus, Landgrafenstraße 15, 44652 Herne, Germany,'], 'affiliations': [{'raw_affiliation_string': 'Rheumazentrum Ruhrgebiet, St.-Josefs-Krankenhaus, Landgrafenstraße 15, 44652 Herne, Germany,', 'institution_ids': ['https://openalex.org/I4210091869']}]}], 'countries_distinct_count': 3, 'institutions_distinct_count': 4, 'corresponding_author_ids': [], 'corresponding_institution_ids': [], 'apc_list': {'value': 3390, 'currency': 'EUR', 'value_usd': 4390, 'provenance': 'doaj'}, 'apc_paid': None, 'fwci': 6.954, 'has_fulltext': True, 'fulltext_origin': 'ngrams', 'cited_by_count': 806, 'citation_normalized_percentile': {'value': 0.999829, 'is_in_top_1_percent': True, 'is_in_top_10_percent': True}, 'cited_by_percentile_year': {'min': 99, 'max': 100}, 'biblio': {'volume': '23', 'issue': '2', 'first_page': '61', 'last_page': '66'}, 'is_retracted': False, 'is_paratext': False, 'primary_topic': {'id': 'https://openalex.org/T11092', 'display_name': 'Classification and Treatment of Spondyloarthritis', 'score': 1.0, 'subfield': {'id': 'https://openalex.org/subfields/2745', 'display_name': 'Rheumatology'}, 'field': {'id': 'https://openalex.org/fields/27', 'display_name': 'Medicine'}, 'domain': {'id': 'https://openalex.org/domains/4', 'display_name': 'Health Sciences'}}, 'topics': [{'id': 'https://openalex.org/T11092', 'display_name': 'Classification and Treatment of Spondyloarthritis', 'score': 1.0, 'subfield': {'id': 'https://openalex.org/subfields/2745', 'display_name': 'Rheumatology'}, 'field': {'id': 'https://openalex.org/fields/27', 'display_name': 'Medicine'}, 'domain': {'id': 'https://openalex.org/domains/4', 'display_name': 'Health Sciences'}}, {'id': 'https://openalex.org/T10469', 'display_name': 'Reciprocal Development of TH17 and Treg Cells', 'score': 0.9979, 'subfield': {'id': 'https://openalex.org/subfields/2403', 'display_name': 'Immunology'}, 'field': {'id': 'https://openalex.org/fields/24', 'display_name': 'Immunology and Microbiology'}, 'domain': {'id': 'https://openalex.org/domains/1', 'display_name': 'Life Sciences'}}, {'id': 'https://openalex.org/T10308', 'display_name': 'Systemic Lupus Erythematosus and Antiphospholipid Syndrome', 'score': 0.9977, 'subfield': {'id': 'https://openalex.org/subfields/2745', 'display_name': 'Rheumatology'}, 'field': {'id': 'https://openalex.org/fields/27', 'display_name': 'Medicine'}, 'domain': {'id': 'https://openalex.org/domains/4', 'display_name': 'Health Sciences'}}], 'keywords': [{'id': 'https://openalex.org/keywords/hla-b27', 'display_name': 'HLA-B27', 'score': 0.607447}, {'id': 'https://openalex.org/keywords/ankylosing-spondylitis', 'display_name': 'Ankylosing Spondylitis', 'score': 0.561156}, {'id': 'https://openalex.org/keywords/reactive-arthritis', 'display_name': 'Reactive arthritis', 'score': 0.5349798}, {'id': 'https://openalex.org/keywords/spondylitis', 'display_name': 'Spondylitis', 'score': 0.4906377}, {'id': 'https://openalex.org/keywords/adult-onset-stills-disease', 'display_name': "Adult-onset Still's disease", 'score': 0.43902758}], 'concepts': [{'id': 'https://openalex.org/C2778091532', 'wikidata': 'https://www.wikidata.org/wiki/Q420574', 'display_name': 'HLA-B27', 'level': 4, 'score': 0.9430559}, {'id': 'https://openalex.org/C71924100', 'wikidata': 'https://www.wikidata.org/wiki/Q11190', 'display_name': 'Medicine', 'level': 0, 'score': 0.931471}, {'id': 'https://openalex.org/C2777402515', 'wikidata': 'https://www.wikidata.org/wiki/Q52849', 'display_name': 'Ankylosing spondylitis', 'level': 2, 'score': 0.9100952}, {'id': 'https://openalex.org/C198451711', 'wikidata': 'https://www.wikidata.org/wiki/Q327657', 'display_name': 'Rheumatology', 'level': 2, 'score': 0.65869844}, {'id': 'https://openalex.org/C2777767895', 'wikidata': 'https://www.wikidata.org/wiki/Q4691924', 'display_name': 'Age of onset', 'level': 3, 'score': 0.64187515}, {'id': 'https://openalex.org/C126322002', 'wikidata': 'https://www.wikidata.org/wiki/Q11180', 'display_name': 'Internal medicine', 'level': 1, 'score': 0.62029034}, {'id': 'https://openalex.org/C2777365958', 'wikidata': 'https://www.wikidata.org/wiki/Q1327700', 'display_name': 'Reactive arthritis', 'level': 3, 'score': 0.5349798}, {'id': 'https://openalex.org/C2779134260', 'wikidata': 'https://www.wikidata.org/wiki/Q12136', 'display_name': 'Disease', 'level': 2, 'score': 0.4937149}, {'id': 'https://openalex.org/C2779650986', 'wikidata': 'https://www.wikidata.org/wiki/Q2165411', 'display_name': 'Spondylitis', 'level': 3, 'score': 0.4906377}, {'id': 'https://openalex.org/C90924648', 'wikidata': 'https://www.wikidata.org/wiki/Q120569', 'display_name': 'Gastroenterology', 'level': 1, 'score': 0.45631465}, {'id': 'https://openalex.org/C2910723750', 'wikidata': 'https://www.wikidata.org/wiki/Q1187697', 'display_name': "Adult-onset Still's disease", 'level': 3, 'score': 0.43902758}, {'id': 'https://openalex.org/C2776194053', 'wikidata': 'https://www.wikidata.org/wiki/Q280027', 'display_name': 'Uveitis', 'level': 2, 'score': 0.42052382}, {'id': 'https://openalex.org/C187212893', 'wikidata': 'https://www.wikidata.org/wiki/Q123028', 'display_name': 'Pediatrics', 'level': 1, 'score': 0.37587425}, {'id': 'https://openalex.org/C203014093', 'wikidata': 'https://www.wikidata.org/wiki/Q101929', 'display_name': 'Immunology', 'level': 1, 'score': 0.16087505}, {'id': 'https://openalex.org/C188280979', 'wikidata': 'https://www.wikidata.org/wiki/Q911125', 'display_name': 'Human leukocyte antigen', 'level': 3, 'score': 0.15361238}, {'id': 'https://openalex.org/C147483822', 'wikidata': 'https://www.wikidata.org/wiki/Q103537', 'display_name': 'Antigen', 'level': 2, 'score': 0.0}], 'mesh': [{'descriptor_ui': 'D003951', 'descriptor_name': 'Diagnostic Errors', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': True}, {'descriptor_ui': 'D015796', 'descriptor_name': 'HLA-B27 Antigen', 'qualifier_ui': 'Q000276', 'qualifier_name': 'immunology', 'is_major_topic': True}, {'descriptor_ui': 'D013167', 'descriptor_name': 'Spondylitis, Ankylosing', 'qualifier_ui': 'Q000175', 'qualifier_name': 'diagnosis', 'is_major_topic': True}, {'descriptor_ui': 'D013167', 'descriptor_name': 'Spondylitis, Ankylosing', 'qualifier_ui': 'Q000453', 'qualifier_name': 'epidemiology', 'is_major_topic': True}, {'descriptor_ui': 'D014606', 'descriptor_name': 'Uveitis, Anterior', 'qualifier_ui': 'Q000453', 'qualifier_name': 'epidemiology', 'is_major_topic': True}, {'descriptor_ui': 'D000208', 'descriptor_name': 'Acute Disease', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D000328', 'descriptor_name': 'Adult', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D017668', 'descriptor_name': 'Age of Onset', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D000368', 'descriptor_name': 'Aged', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D000369', 'descriptor_name': 'Aged, 80 and over', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D005260', 'descriptor_name': 'Female', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D015796', 'descriptor_name': 'HLA-B27 Antigen', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D006801', 'descriptor_name': 'Humans', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D008297', 'descriptor_name': 'Male', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D008875', 'descriptor_name': 'Middle Aged', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D012189', 'descriptor_name': 'Retrospective Studies', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D013167', 'descriptor_name': 'Spondylitis, Ankylosing', 'qualifier_ui': 'Q000276', 'qualifier_name': 'immunology', 'is_major_topic': False}, {'descriptor_ui': 'D013167', 'descriptor_name': 'Spondylitis, Ankylosing', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}, {'descriptor_ui': 'D013167', 'descriptor_name': 'Spondylitis, Ankylosing', 'qualifier_ui': 'Q000150', 'qualifier_name': 'complications', 'is_major_topic': False}, {'descriptor_ui': 'D014606', 'descriptor_name': 'Uveitis, Anterior', 'qualifier_ui': 'Q000150', 'qualifier_name': 'complications', 'is_major_topic': False}, {'descriptor_ui': 'D014606', 'descriptor_name': 'Uveitis, Anterior', 'qualifier_ui': '', 'qualifier_name': None, 'is_major_topic': False}], 'locations_count': 2, 'locations': [{'is_oa': False, 'landing_page_url': 'https://doi.org/10.1007/s00296-002-0237-4', 'pdf_url': None, 'source': {'id': 'https://openalex.org/S50823678', 'display_name': 'Rheumatology International', 'issn_l': '0172-8172', 'issn': ['0172-8172', '1437-160X'], 'is_oa': False, 'is_in_doaj': False, 'is_core': True, 'host_organization': 'https://openalex.org/P4310319900', 'host_organization_name': 'Springer Science+Business Media', 'host_organization_lineage': ['https://openalex.org/P4310319965', 'https://openalex.org/P4310319900'], 'host_organization_lineage_names': ['Springer Nature', 'Springer Science+Business Media'], 'type': 'journal'}, 'license': None, 'license_id': None, 'version': None, 'is_accepted': False, 'is_published': False}, {'is_oa': False, 'landing_page_url': 'https://pubmed.ncbi.nlm.nih.gov/12634937', 'pdf_url': None, 'source': {'id': 'https://openalex.org/S4306525036', 'display_name': 'PubMed', 'issn_l': None, 'issn': None, 'is_oa': False, 'is_in_doaj': False, 'is_core': False, 'host_organization': 'https://openalex.org/I1299303238', 'host_organization_name': 'National Institutes of Health', 'host_organization_lineage': ['https://openalex.org/I1299303238'], 'host_organization_lineage_names': ['National Institutes of Health'], 'type': 'repository'}, 'license': None, 'license_id': None, 'version': None, 'is_accepted': False, 'is_published': False}], 'best_oa_location': None, 'sustainable_development_goals': [{'display_name': 'Zero hunger', 'score': 0.74, 'id': 'https://metadata.un.org/sdg/2'}], 'grants': [], 'datasets': [], 'versions': [], 'referenced_works_count': 12, 'referenced_works': ['https://openalex.org/W15228753', 'https://openalex.org/W1966305644', 'https://openalex.org/W1997242331', 'https://openalex.org/W2039389429', 'https://openalex.org/W2059465919', 'https://openalex.org/W2070044107', 'https://openalex.org/W2075299227', 'https://openalex.org/W2089375252', 'https://openalex.org/W2167418901', 'https://openalex.org/W2338072779', 'https://openalex.org/W2401899336', 'https://openalex.org/W2418744250'], 'related_works': ['https://openalex.org/W4319292977', 'https://openalex.org/W4299397508', 'https://openalex.org/W3022728099', 'https://openalex.org/W3011936763', 'https://openalex.org/W2916045276', 'https://openalex.org/W2215893208', 'https://openalex.org/W2094312957', 'https://openalex.org/W2085745311', 'https://openalex.org/W2073732400', 'https://openalex.org/W2021562477'], 'abstract_inverted_index': None, 'cited_by_api_url': 'https://api.openalex.org/works?filter=cites:W1539633218', 'counts_by_year': [{'year': 2024, 'cited_by_count': 22}, {'year': 2023, 'cited_by_count': 45}, {'year': 2022, 'cited_by_count': 55}, {'year': 2021, 'cited_by_count': 51}, {'year': 2020, 'cited_by_count': 49}, {'year': 2019, 'cited_by_count': 59}, {'year': 2018, 'cited_by_count': 45}, {'year': 2017, 'cited_by_count': 57}, {'year': 2016, 'cited_by_count': 32}, {'year': 2015, 'cited_by_count': 40}, {'year': 2014, 'cited_by_count': 59}, {'year': 2013, 'cited_by_count': 59}, {'year': 2012, 'cited_by_count': 49}], 'updated_date': '2024-09-12T18:26:42.101967', 'created_date': '2016-06-24'}