Pregnancy Outcomes in a Diverse US Lupus Cohort

OBJECTIVE

Although the population of patients with systemic lupus erythematosus (SLE) is racially and ethnically diverse, many study populations are homogeneous. Further, data are often lacking on critical factors, such as antiphospholipid antibodies (aPLs). We investigated live birth rates in patients with SLE at Kaiser Permanente Northern California, including race and ethnicity and aPL data.

METHODS

Electronic health records of pregnancies with outcomes observed from 2011 to 2020 were identified among patients with SLE. Prevalent SLE was defined as two or more International Classification of Diseases-coded visits seven or more days apart before the last menstrual period. We summarized patient characteristics, medication orders, health care use, and medication use. Pregnancy outcomes (live birth, stillbirth, spontaneous abortion, ectopic pregnancy, and molar pregnancy) were presented overall and stratified by race and ethnicity, aPL status, and nephritis history.

RESULTS

We identified 657 pregnancies among 453 patients with SLE. The cohort was diverse, reflecting the Northern California population (27% Asian, 26% Hispanic, 26% Non-Hispanic White, 13% Non-Hispanic Black, 5% multiracial, and approximately 2% Pacific Islander and Native American). Approximately 74% of observed pregnancies ended in live birth, 23% resulted in spontaneous abortion, 2% were ectopic or molar pregnancies, and <1% were stillbirths. There was limited variability in live births by race and ethnic group (72%-79%), aPL status (69.5%-77%), and nephritis history (71%-75%).

CONCLUSION

Our findings are consistent with previous studies; however, some methodologic differences may yield a range of live birth rates. We found that approximately 74% of pregnancies in patients with SLE ended in live birth, with modest variability in spontaneous abortion by race and ethnicity, nephritis history, and aPL status.

Reconciling Between Medication Orders and Medication Fills for Lupus in Pregnancy

OBJECTIVE

Most studies consider either medications ordered or filled, but not both. Medication underuse based on filling data cannot necessarily be ascribed to patient nonadherence. Using both data sources, we quantified primary medication adherence in a cohort of prevalent systemic lupus erythematosus (SLE) pregnancies.

METHODS

We identified 419 pregnancies in Kaiser Permanente Northern California in patients with prevalent SLE from 2011 to 2020. We calculated the number of physician-initiated orders or pharmacy-initiated reorders during pregnancy and a comparable 9-month window the year before (prepregnancy) and the proportion of orders ever filled and filled within 30 days for hydroxychloroquine (HCQ), azathioprine, and corticosteroids. For pregnancies without an order or reorder, we identified the proportion with previous prescription fills overlapping into the respective study period.

RESULTS

New orders for lupus medications were usually filled. HCQ was prescribed most often (45.8% pregnancies) and usually filled (89.7% in prepregnancy, 93.2% during pregnancy). The majority filled within 30 days (80.5% prepregnancy, 83.3% pregnancy). Some pregnancies without new HCQ orders had continuous refills from prior orders; 53% of 2011-2015 pregnancies either had a new order or fill coverage from a previous period, compared to 63.2% of pregnancies delivering in 2016-2019. Corticosteroid fill frequencies were 90.6% in prepregnancy and 83.6% during pregnancy. Fewer patients used azathioprine; however, most new orders were filled (94.3% prepregnancy, 91.7% pregnancy). For azathioprine and corticosteroids, fill rates were modestly higher in prepregnancy compared to pregnancy.

CONCLUSION

We observed that patients have high adherence to filling new orders for lupus medications, such as HCQ and azathioprine, in pregnancy.

Prediction of alpha-helices in proteins with the hydrophobic strip-of-helix template and distributions of other amino acids around the hydrophobic strip

Upon addition of requirements for highly characteristic distributions of helix-stabilizing residues to an alpha-helix predictor based upon identification of a longitudinal, hydrophobic strip-of-helix pattern, maximal sensitivity and efficiency scores approached 50% levels at a high degree of stringency. The hydrophobic strip-of-helix template ([symbol: see text], joined in a circle) was applied to 247 helices to maximize the strip-of-helix hydrophobicity index (SOHHI; the mean hydrophobicity of residues in [symbol: see text] positions). Statistically significant increases or decreases in the frequencies of certain residues are observed in some [symbol: see text] and [symbol: see text] positions: [symbol: see text] in the helix (including N- and C-terminal [symbol: see text] in the helix): Leu, Ile, Val, Phe, and Met; first [symbol: see text] positions in extensions of the template to surrounding segments: not increased Leu, Ile, Val, Phe, or Met; N-terminal [symbol: see text]: Asp, Glu; C-terminal [symbol: see text] and the first [symbol: see text] after the helix: His, Lys, Arg; N-terminal [symbol: see text]: Asn; C-terminal [symbol: see text]: Gln; smallest residue in longitudinal strip-of-helix: Ala or Val at crossing points between helices. An algorithm was then derived to indicate alpha-helices by merging predictions with templates [symbol: see text] and [symbol: see text], where the SOHHI > or = 3.0 in the Kyte-Doolittle scale. Relative to the baseline prediction using only the template, more elaborate rules using combinations of other structural patterns produced more efficient (49 versus 42%, respectively) but less sensitive (32 versus 42%, respectively) predictions when the prediction was required to overlap substantially with the known helix. These maximal sensitivities and efficiencies imply that some helices may be formed in folding intermediates but are lost upon coalescence of the final form. Better predictions of protein structure from the primary sequence may require modeling of competing interactions of local structures in folding intermediates.

Critical functional role of the COOH-terminal ends of longitudinal hydrophobic strips in alpha-helices of T4 lysozyme

The sensitivity of bacteriophage T4 lysozyme function to amino acid substitutions at defined positions in and around the longitudinal, hydrophobic strips of 9 alpha-helices was assessed after systematic replacement of each residue in the protein with a series of 13 amino acids. The hydrophobic strips were defined by identifying the longitudinal sectors in the helices with the highest mean residue hydrophobicities. Sensitivity to mutation (the percentage of replacements leading to loss of function) was calculated for each residue in the following positions: whole protein, helices, hydrophobic strips, other positions within the helices, and various positions within the hydrophobic strips as well as their extensions beyond the helices. Substitutions at positions in the hydrophobic strips led more frequently to loss of function than substitutions in the protein as a whole. One subset, the COOH-terminal hydrophobic strip residues, is apparently critical; substitutions of these residues (but not of their NH2-terminal counterparts) led at least as frequently to loss of function as substitutions of solvent-inaccessible residues, and nearly as frequently as substitutions of the most highly conserved residues.

Residues in the longitudinal, hydrophobic strip-of-helix relate to terminations and crossings of alpha-helices

An alpha-helix terminates when the virtual extension of its most hydrophobic, longitudinal strip containing Leu, Ile, Val, Phe, and Met lacks those residues. In each of 247 helices a template was fitted to maximize the mean hydrophobicity of positions forming a longitudinal strip-of-helix. The template was then extended into sequences beyond the ends of the helices. Leu, Ile, Val, Phe, and Met occurred in positions in the longitudinal strip-of-helix at an increased frequency (p less than 0.001), but in the first and second positions beyond either end of each true helix, they occurred at the same frequency as for their empirical distribution over all the proteins. Excesses of Asp and Glu were found in the N-terminal loop, and of Arg, His, and Lys in specific positions about the C terminus of helices. The longitudinal hydrophobic strip, the smallest amino acid in that strip, and charged amino acids in that strip, related to rotational and longitudinal orientation of alpha-helices in 15 proteins. Adjacent helices generally crossed through their longitudinal hydrophobic strips. They usually crossed through the smallest residue in the strip. Charged residues, when they occurred in the strips, were excluded from the crossing regions.