Background/Purpose: We examined first degree relatives (FDRs) of patients with ankylosing spondylitis (AS) patients with chronic inflammatory back pain (CIBP), non-inflammatory CBP (NICBP) and no CBP for clinical features (comparing those with and without CIBP and with people participating in NHANES 2009-2010 with CBP. We examined HLA-B27 alleles and persistence of IBP over time in those with CBP.

Methods: 548 FDRs of 302 AS probands were divided into 3 groups, excluding those with a diagnosis of AS at baseline visit and, within each group, blood relatives: 1) No CBP (only subjects > 40 years of age at study visit who never had CBP) (n=159); 2) NICBP (n=79), and 3) CIBP (n=152). The white FDRs with CBP between ages 20 and 69 years were compared with 772 participants in NHANES 2009-2010 with CBP, to whom the same questionnaire was administered. HLA-B allele typing was carried out by single stranded conformation polymorphism analysis. FDRs were invited to return for a second visit either by mail or by repeat clinical evaluation.

Results: 1) FDRs with CIBP were younger than those with NICBP (45.1 years versus 55.6 years, p=0.0002), and had higher frequency of heel pain (52.7% versus 43.4%, p=0.005). HLA-B27 occurred in 57% of FDR’s with CIBP compared 49.4% with NICBP (p=n.s.) and 39.6% of those >40 years of age at assessment with no CBP (p=0.005, OR=1.9).

2) Comparing 206 unrelated white FDRs (there were too few nonwhite FDR’s available for meaningful analysis) with 772 white participants in NHANES 2009-2010 with CBP, there were no significant differences in features of IBP, in fact some features (pain improving as the day progresses, AM stiffness, awakening the second half of the night) were less common in FDRs with CBP compared with the general population (Table 1). On the other hand, other features of SpA (earlier age at CBP onset, uveitis, psoriasis) were more frequent in FDRs of AS patients.

* p-value based on unvariable model ** p-value based on multivariable model (adjusted for age and gender)

3) Of 23 patients with CIBP at baseline seen again 67.04+/- 31.02 months later, 16 (73%) still had CIBP, whereas only four (33%) of 13 NICBP patients (31%) seen 61.23 +/- 31.84 months later were still symptomatic. Of the remaining nine, three (23%) developed CIBP and six (46%) had symptoms resolve. Of the 13 without CBP at baseline seen 75.5 +/- 29.9 months later, 11(85%) remained asymptomatic, two (15%) developed CIBP and none developed noninflammatory CBP.

Conclusion: These data suggest FDRs of AS patients with CIBP have a younger age at onset, a higher frequency of heel pain, and higher frequency of HLA-B27 than those FDRs who do not develop CBP and compared to the general US population (though other features of CIBP were not more frequently seen). CIBP in FDRs of AS patients remains stable and chronic over time in most, suggesting a need for long term diagnostic and treatment approaches in this group.

« Back to 2018 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/chronic-back-pain-cbp-in-first-degree-relatives-fdrs-of-patient-with-ankylosing-spondylitis-as-comparison-with-the-us-population-hla-b27-frequency-and-persistence-of-symptoms-over-time/